diff --git a/circuits/smt/smtinsert.circom b/circuits/smt/smtprocessor.circom
similarity index 98%
rename from circuits/smt/smtinsert.circom
rename to circuits/smt/smtprocessor.circom
index 4206ef9..ac45b60 100644
--- a/circuits/smt/smtinsert.circom
+++ b/circuits/smt/smtprocessor.circom
@@ -110,11 +110,11 @@ include "../bitify.circom";
 include "../comparators.circom";
 include "../switcher.circom";
 include "smtlevins.circom";
-include "smtinsertlevel.circom";
-include "smtinsertsm.circom";
+include "smtprocessorlevel.circom";
+include "smtprocessorsm.circom";
 include "smthash.circom";
 
-template SMTInsert(nLevels) {
+template SMTProcessor(nLevels) {
     signal input oldRoot;
     signal input newRoot;
     signal input siblings[nLevels];
@@ -156,7 +156,7 @@ template SMTInsert(nLevels) {
 
     component sm[nLevels];
     for (var i=0; i<nLevels; i++) {
-        sm[i] = SMTInsertSM();
+        sm[i] = SMTProcessorSM();
         if (i==0) {
             sm[i].prev_top <== enabled;
             sm[i].prev_old0 <== 0;
@@ -182,7 +182,7 @@ template SMTInsert(nLevels) {
 
     component levels[nLevels];
     for (var i=nLevels-1; i != -1; i--) {
-        levels[i] = SMTInsertLevel();
+        levels[i] = SMTProcessorLevel();
 
         levels[i].st_top <== sm[i].st_top;
         levels[i].st_old0 <== sm[i].st_old0;
diff --git a/circuits/smt/smtinsertlevel.circom b/circuits/smt/smtprocessorlevel.circom
similarity index 97%
rename from circuits/smt/smtinsertlevel.circom
rename to circuits/smt/smtprocessorlevel.circom
index 85757aa..5a1f208 100644
--- a/circuits/smt/smtinsertlevel.circom
+++ b/circuits/smt/smtprocessorlevel.circom
@@ -2,7 +2,7 @@
 
 /******
 
-SMTInsertLevel
+SMTProcessorLevel
 
 This circuit has 2 has
 
@@ -23,7 +23,7 @@ H' is the Hash function with the inputs shifted acordingly.
 *****/
 
 
-template SMTInsertLevel() {
+template SMTProcessorLevel() {
     signal input st_top;
     signal input st_old0;
     signal input st_bot;
diff --git a/circuits/smt/smtinsertsm.circom b/circuits/smt/smtprocessorsm.circom
similarity index 93%
rename from circuits/smt/smtinsertsm.circom
rename to circuits/smt/smtprocessorsm.circom
index 5a51536..79ed0cb 100644
--- a/circuits/smt/smtinsertsm.circom
+++ b/circuits/smt/smtprocessorsm.circom
@@ -1,5 +1,5 @@
 /***************************************************************************************************
-Each level on a SMTInsert has a state.
+Each level on a SMTProcessor has a state.
 
 The state of the level depends on the state of te botom level and on `xor` and
 `is0` signals.
@@ -9,18 +9,18 @@ The state of the level depends on the state of te botom level and on `xor` and
 `xor` signal is 0 if the index bit at the current level is the same in the old
 and the new index, and 1 if it is different.
 
-`is0` signal, is 1 if we are inserting in an empty leaf and 0 if we are inserting
-in a leaf that contains an element.
+`is0` signal, is 1 if we are inserting/deleting in an empty leaf and 0 if we
+are inserting/deleting in a leaf that contains an element.
 
 The states are:
 
 top: While the index bits of the old and new insex in the top level is the same, whe are in the top state.
-old0 and old1: When the we reach insert level,  we go to old0 and old1 states
+old0 and old1: When the we reach processor level,  we go to old0 and old1 states
 according to `is0` signal.
 btn: Once in old1 we go to btn until xor=1
-new1: This level is reached when xor=1. Here is where we insert the hash of the
+new1: This level is reached when xor=1. Here is where we insert/delete the hash of the
 old and the new trees with just one element.
-na: Not appliable.  After inserting it, we go to the na level.
+na: Not appliable.  After processing it, we go to the na level.
 
 
 Fnction
@@ -72,7 +72,7 @@ fnc[0]  fnc[1]
 
 ***************************************************************************************************/
 
-template SMTInsertSM() {
+template SMTProcessorSM() {
   signal input xor;
   signal input is0;
   signal input levIns;
diff --git a/src/smt.js b/src/smt.js
index 585c017..0cb8ea7 100644
--- a/src/smt.js
+++ b/src/smt.js
@@ -37,6 +37,55 @@ class SMT {
         return res;
     }
 
+    async update(_key, _newValue) {
+        const key = bigInt(_key);
+        const newValue = bigInt(_newValue);
+
+
+        const resFind = await this.find(key);
+        const res = {};
+        res.oldRoot = this.root;
+        res.oldKey = key;
+        res.oldValue = resFind.foundValue;
+        res.newKey = key;
+        res.newValue = newValue;
+        res.siblings = resFind.siblings;
+
+        const ins = [];
+        const dels = [];
+
+        let rtOld = smtHash([1, key, resFind.foundValue]);
+        let rtNew = smtHash([1, key, newValue]);
+        ins.push([rtNew, [1, key, newValue ]]);
+        dels.push(rtOld);
+
+        const keyBits = this._splitBits(key);
+        for (let level = resFind.siblings.length-1; level >=0; level--) {
+            let oldNode, newNode;
+            const sibling = resFind.siblings[level];
+            if (keyBits[level]) {
+                oldNode = [sibling, rtOld];
+                newNode = [sibling, rtNew];
+            } else {
+                oldNode = [rtOld, sibling, ];
+                newNode = [rtNew, sibling, ];
+            }
+            rtOld = smtHash(oldNode);
+            rtNew = smtHash(newNode);
+            dels.push(rtOld);
+            ins.push([rtNew, newNode]);
+        }
+
+        res.newRoot = rtNew;
+
+        await this.db.multiIns(ins);
+        await this.db.setRoot(rtNew);
+        this.root = rtNew;
+        await this.db.multiDel(dels);
+
+        return res;
+    }
+
     async delete(_key) {
         const key = bigInt(_key);
 
@@ -44,7 +93,7 @@ class SMT {
         if (!resFind.found) throw new Error("Key does not exists");
 
         const res = {
-            sibblings: [],
+            siblings: [],
             delKey: key,
             delValue: resFind.foundValue
         };
@@ -55,16 +104,15 @@ class SMT {
         let rtNew;
         dels.push(rtOld);
 
-
         let mixed;
-        if (resFind.sibblings.length > 0) {
-            const record = await this.db.get(resFind.sibblings[resFind.sibblings.length - 1]);
+        if (resFind.siblings.length > 0) {
+            const record = await this.db.get(resFind.siblings[resFind.siblings.length - 1]);
             if ((record.length == 3)&&(record[0].equals(bigInt.one))) {
                 mixed = false;
                 res.oldKey = record[1];
                 res.oldValue = record[2];
                 res.isOld0 = false;
-                rtNew = resFind.sibblings[resFind.sibblings.length - 1];
+                rtNew = resFind.siblings[resFind.siblings.length - 1];
             } else if (record.length == 2) {
                 mixed = true;
                 res.oldKey = key;
@@ -83,12 +131,12 @@ class SMT {
 
         const keyBits = this._splitBits(key);
 
-        for (let level = resFind.sibblings.length-1; level >=0; level--) {
-            let newSibling = resFind.sibblings[level];
-            if ((level == resFind.sibblings.length-1)&&(!res.isOld0)) {
+        for (let level = resFind.siblings.length-1; level >=0; level--) {
+            let newSibling = resFind.siblings[level];
+            if ((level == resFind.siblings.length-1)&&(!res.isOld0)) {
                 newSibling = bigInt.zero;
             }
-            const oldSibling = resFind.sibblings[level];
+            const oldSibling = resFind.siblings[level];
             if (keyBits[level]) {
                 rtOld = smtHash([oldSibling, rtOld]);
             } else {
@@ -100,7 +148,7 @@ class SMT {
             }
 
             if (mixed) {
-                res.sibblings.unshift(resFind.sibblings[level]);
+                res.siblings.unshift(resFind.siblings[level]);
                 let newNode;
                 if (keyBits[level]) {
                     newNode = [newSibling, rtNew];
@@ -137,19 +185,19 @@ class SMT {
 
         if (resFind.found) throw new Error("Key already exists");
 
-        res.sibblings = resFind.sibblings;
+        res.siblings = resFind.siblings;
         let mixed;
 
         if (!resFind.isOld0) {
             const oldKeyits = this._splitBits(resFind.notFoundKey);
-            for (let i= res.sibblings.length; oldKeyits[i] == newKeyBits[i]; i++) {
-                res.sibblings.push(bigInt.zero);
+            for (let i= res.siblings.length; oldKeyits[i] == newKeyBits[i]; i++) {
+                res.siblings.push(bigInt.zero);
             }
             rtOld = smtHash([1, resFind.notFoundKey, resFind.notFoundValue]);
-            res.sibblings.push(rtOld);
+            res.siblings.push(rtOld);
             addedOne = true;
             mixed = false;
-        } else if (res.sibblings.length >0) {
+        } else if (res.siblings.length >0) {
             mixed = true;
             rtOld = bigInt.zero;
         }
@@ -160,12 +208,12 @@ class SMT {
         let rt = smtHash([1, key, value]);
         inserts.push([rt,[1, key, value]] );
 
-        for (let i=res.sibblings.length-1; i>=0; i--) {
-            if ((i<res.sibblings.length-1)&&(!res.sibblings[i].isZero())) {
+        for (let i=res.siblings.length-1; i>=0; i--) {
+            if ((i<res.siblings.length-1)&&(!res.siblings[i].isZero())) {
                 mixed = true;
             }
             if (mixed) {
-                const oldSibling = resFind.sibblings[i];
+                const oldSibling = resFind.siblings[i];
                 if (newKeyBits[i]) {
                     rtOld = smtHash([oldSibling, rtOld]);
                 } else {
@@ -177,18 +225,18 @@ class SMT {
 
             let newRt;
             if (newKeyBits[i]) {
-                newRt = smtHash([res.sibblings[i], rt]);
-                inserts.push([newRt,[res.sibblings[i], rt]] );
+                newRt = smtHash([res.siblings[i], rt]);
+                inserts.push([newRt,[res.siblings[i], rt]] );
             } else {
-                newRt = smtHash([rt, res.sibblings[i]]);
-                inserts.push([newRt,[rt, res.sibblings[i]]] );
+                newRt = smtHash([rt, res.siblings[i]]);
+                inserts.push([newRt,[rt, res.siblings[i]]] );
             }
             rt = newRt;
         }
 
-        if (addedOne) res.sibblings.pop();
-        while ((res.sibblings.length>0) && (res.sibblings[res.sibblings.length-1].isZero())) {
-            res.sibblings.pop();
+        if (addedOne) res.siblings.pop();
+        while ((res.siblings.length>0) && (res.siblings[res.siblings.length-1].isZero())) {
+            res.siblings.pop();
         }
         res.oldKey = resFind.notFoundKey;
         res.oldValue = resFind.notFoundValue;
@@ -216,7 +264,7 @@ class SMT {
         if (root.isZero()) {
             res = {
                 found: false,
-                sibblings: [],
+                siblings: [],
                 notFoundKey: key,
                 notFoundValue: bigInt.zero,
                 isOld0: true
@@ -230,14 +278,14 @@ class SMT {
             if (record[1].equals(key)) {
                 res = {
                     found: true,
-                    sibblings: [],
+                    siblings: [],
                     foundValue: record[2],
                     isOld0: false
                 };
             } else {
                 res = {
                     found: false,
-                    sibblings: [],
+                    siblings: [],
                     notFoundKey: record[1],
                     notFoundValue: record[2],
                     isOld0: false
@@ -246,10 +294,10 @@ class SMT {
         } else {
             if (keyBits[level] == 0) {
                 res = await this._find(key, keyBits, record[0], level+1);
-                res.sibblings.unshift(record[1]);
+                res.siblings.unshift(record[1]);
             } else {
                 res = await this._find(key, keyBits, record[1], level+1);
-                res.sibblings.unshift(record[0]);
+                res.siblings.unshift(record[0]);
             }
         }
         return res;
diff --git a/test/circuits/smtinsert10_test.circom b/test/circuits/smtinsert10_test.circom
deleted file mode 100644
index ca866c1..0000000
--- a/test/circuits/smtinsert10_test.circom
+++ /dev/null
@@ -1,3 +0,0 @@
-include "../../circuits/smt/smtinsert.circom";
-
-component main = SMTInsert(10);
diff --git a/test/circuits/smtprocessor10_test.circom b/test/circuits/smtprocessor10_test.circom
new file mode 100644
index 0000000..ecf15d0
--- /dev/null
+++ b/test/circuits/smtprocessor10_test.circom
@@ -0,0 +1,3 @@
+include "../../circuits/smt/smtprocessor.circom";
+
+component main = SMTProcessor(10);
diff --git a/test/smt.js b/test/smt.js
index 4459645..a12cdd7 100644
--- a/test/smt.js
+++ b/test/smt.js
@@ -16,7 +16,7 @@ function print(circuit, w, s) {
 async function testInsert(tree, key, value, circuit, log ) {
 
     const res = await tree.insert(key,value);
-    let siblings = res.sibblings;
+    let siblings = res.siblings;
     while (siblings.length<10) siblings.push(bigInt(0));
 
     const w = circuit.calculateWitness({
@@ -38,7 +38,7 @@ async function testInsert(tree, key, value, circuit, log ) {
 
 async function testDelete(tree, key, circuit) {
     const res = await tree.delete(key);
-    let siblings = res.sibblings;
+    let siblings = res.siblings;
     while (siblings.length<10) siblings.push(bigInt(0));
 
     const w = circuit.calculateWitness({
@@ -59,6 +59,29 @@ async function testDelete(tree, key, circuit) {
     assert(root1.equals(res.newRoot));
 }
 
+async function testUpdate(tree, key, newValue, circuit) {
+    const res = await tree.update(key, newValue);
+    let siblings = res.siblings;
+    while (siblings.length<10) siblings.push(bigInt(0));
+
+    const w = circuit.calculateWitness({
+        fnc: [0,1],
+        oldRoot: res.oldRoot,
+        newRoot: res.newRoot,
+        siblings: siblings,
+        oldKey: res.oldKey,
+        oldValue: res.oldValue,
+        isOld0: 0,
+        newKey: res.newKey,
+        newValue: res.newValue
+    });
+
+    const root1 = w[circuit.getSignalIdx("main.topSwitcher.outR")];
+
+    assert(circuit.checkWitness(w));
+    assert(root1.equals(res.newRoot));
+}
+
 
 describe("SMT test", function () {
     let circuit;
@@ -67,11 +90,11 @@ describe("SMT test", function () {
     this.timeout(100000);
 
     before( async () => {
-        const cirDef = await compiler(path.join(__dirname, "circuits", "smtinsert10_test.circom"));
+        const cirDef = await compiler(path.join(__dirname, "circuits", "smtprocessor10_test.circom"));
 
         circuit = new snarkjs.Circuit(cirDef);
 
-        console.log("NConstrains SMTInsert: " + circuit.nConstraints);
+        console.log("NConstrains SMTProcessor: " + circuit.nConstraints);
 
         tree = await smt.newMemEmptyTrie();
     });
@@ -175,7 +198,20 @@ describe("SMT test", function () {
 
     });
     it("Should update an element", async () => {
+        const tree1 = await smt.newMemEmptyTrie();
+        const tree2 = await smt.newMemEmptyTrie();
 
+        await testInsert(tree1,8,88, circuit);
+        await testInsert(tree1,9,99, circuit);
+        await testInsert(tree1,32,3232, circuit);
+
+        await testInsert(tree2,8,888, circuit);
+        await testInsert(tree2,9,999, circuit);
+        await testInsert(tree2,32,323232, circuit);
+
+        await testUpdate(tree1, 8, 888, circuit);
+        await testUpdate(tree1, 9, 999, circuit);
+        await testUpdate(tree1, 32, 323232, circuit);
     });
 
     it("Should verify existance of an element", async () => {
diff --git a/test/smtjs.js b/test/smtjs.js
index b632b0d..eb360ab 100644
--- a/test/smtjs.js
+++ b/test/smtjs.js
@@ -160,4 +160,23 @@ describe("SMT Javascript test", function () {
         assert.equal(Object.keys(tree.db.nodes).length, 0);
     });
 
+    it("Should test update", async () => {
+        const tree1 = await smt.newMemEmptyTrie();
+        const tree2 = await smt.newMemEmptyTrie();
+
+        await tree1.insert(8,88);
+        await tree1.insert(9,99,);
+        await tree1.insert(32,3232);
+
+        await tree2.insert(8,888);
+        await tree2.insert(9,999);
+        await tree2.insert(32,323232);
+
+        await tree1.update(8, 888);
+        await tree1.update(9, 999);
+        await tree1.update(32, 323232);
+
+        assert(tree1.root.equals(tree2.root));
+    });
+
 });