diff --git a/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol b/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
index 0b9cc4f..3658c5d 100644
--- a/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/IncrementalBinaryTree.sol
@@ -31,8 +31,14 @@ library IncrementalBinaryTree {
         uint8 depth,
         uint256 zero
     ) public {
-        require(zero < SNARK_SCALAR_FIELD, "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD");
-        require(depth > 0 && depth <= MAX_DEPTH, "IncrementalBinaryTree: tree depth must be between 1 and 32");
+        require(
+            zero < SNARK_SCALAR_FIELD,
+            "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD"
+        );
+        require(
+            depth > 0 && depth <= MAX_DEPTH,
+            "IncrementalBinaryTree: tree depth must be between 1 and 32"
+        );
 
         self.depth = depth;
 
@@ -48,8 +54,14 @@ library IncrementalBinaryTree {
     /// @param self: Tree data.
     /// @param leaf: Leaf to be inserted.
     function insert(IncrementalTreeData storage self, uint256 leaf) public {
-        require(leaf < SNARK_SCALAR_FIELD, "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD");
-        require(self.numberOfLeaves < 2**self.depth, "IncrementalBinaryTree: tree is full");
+        require(
+            leaf < SNARK_SCALAR_FIELD,
+            "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD"
+        );
+        require(
+            self.numberOfLeaves < 2**self.depth,
+            "IncrementalBinaryTree: tree is full"
+        );
 
         uint256 index = self.numberOfLeaves;
         uint256 hash = leaf;
@@ -69,6 +81,38 @@ library IncrementalBinaryTree {
         self.numberOfLeaves += 1;
     }
 
+    /// @dev Updates a leaf in the tree.
+    /// @param self: Tree data.
+    /// @param leaf: Leaf to be updated.
+    /// @param proofSiblings: Array of the sibling nodes of the proof of membership.
+    /// @param proofPathIndices: Path of the proof of membership.
+    function update(
+        IncrementalTreeData storage self,
+        uint256 leaf,
+        uint256[] calldata proofSiblings,
+        uint8[] calldata proofPathIndices
+    ) public {
+
+        uint256 hash = leaf;
+        for (uint8 i = 0; i < self.depth; i++) {
+            if (proofPathIndices[i] == 0) {
+                if (proofSiblings[i] == self.lastSubtrees[i][1]) {
+                    self.lastSubtrees[i][0] = hash;
+                }
+
+                hash = PoseidonT3.poseidon([hash, proofSiblings[i]]);
+            } else {
+                if (proofSiblings[i] == self.lastSubtrees[i][0]) {
+                    self.lastSubtrees[i][1] = hash;
+                }
+
+                hash = PoseidonT3.poseidon([proofSiblings[i], hash]);
+            }
+        }
+
+        self.root = hash;
+    }
+
     /// @dev Removes a leaf from the tree.
     /// @param self: Tree data.
     /// @param leaf: Leaf to be removed.
@@ -118,9 +162,13 @@ library IncrementalBinaryTree {
         uint256[] calldata proofSiblings,
         uint8[] calldata proofPathIndices
     ) private view returns (bool) {
-        require(leaf < SNARK_SCALAR_FIELD, "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD");
         require(
-            proofPathIndices.length == self.depth && proofSiblings.length == self.depth,
+            leaf < SNARK_SCALAR_FIELD,
+            "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD"
+        );
+        require(
+            proofPathIndices.length == self.depth &&
+                proofSiblings.length == self.depth,
             "IncrementalBinaryTree: length of path is not correct"
         );
 
diff --git a/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol b/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol
index 1934237..84e50c9 100644
--- a/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/IncrementalQuinTree.sol
@@ -31,8 +31,14 @@ library IncrementalQuinTree {
         uint8 depth,
         uint256 zero
     ) public {
-        require(zero < SNARK_SCALAR_FIELD, "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD");
-        require(depth > 0 && depth <= MAX_DEPTH, "IncrementalQuinTree: tree depth must be between 1 and 32");
+        require(
+            zero < SNARK_SCALAR_FIELD,
+            "IncrementalBinaryTree: leaf must be < SNARK_SCALAR_FIELD"
+        );
+        require(
+            depth > 0 && depth <= MAX_DEPTH,
+            "IncrementalQuinTree: tree depth must be between 1 and 32"
+        );
 
         self.depth = depth;
 
@@ -54,8 +60,14 @@ library IncrementalQuinTree {
     /// @param self: Tree data.
     /// @param leaf: Leaf to be inserted.
     function insert(IncrementalTreeData storage self, uint256 leaf) public {
-        require(leaf < SNARK_SCALAR_FIELD, "IncrementalQuinTree: leaf must be < SNARK_SCALAR_FIELD");
-        require(self.numberOfLeaves < 5**self.depth, "IncrementalQuinTree: tree is full");
+        require(
+            leaf < SNARK_SCALAR_FIELD,
+            "IncrementalQuinTree: leaf must be < SNARK_SCALAR_FIELD"
+        );
+        require(
+            self.numberOfLeaves < 5**self.depth,
+            "IncrementalQuinTree: tree is full"
+        );
 
         uint256 index = self.numberOfLeaves;
         uint256 hash = leaf;
@@ -79,6 +91,50 @@ library IncrementalQuinTree {
         self.numberOfLeaves += 1;
     }
 
+    /// @dev Updates a leaf in the tree.
+    /// @param self: Tree data.
+    /// @param leaf: Leaf to be updated.
+    /// @param proofSiblings: Array of the sibling nodes of the proof of membership.
+    /// @param proofPathIndices: Path of the proof of membership.
+    function update(
+        IncrementalTreeData storage self,
+        uint256 leaf,
+        uint256[4][] calldata proofSiblings,
+        uint8[] calldata proofPathIndices
+    ) public {
+        require(
+            verify(self, leaf, proofSiblings, proofPathIndices),
+            "IncrementalQuinTree: leaf is not part of the tree"
+        );
+
+        uint256 hash = self.zeroes[0];
+
+        for (uint8 i = 0; i < self.depth; i++) {
+            uint256[5] memory nodes;
+
+            for (uint8 j = 0; j < 5; j++) {
+                if (j < proofPathIndices[i]) {
+                    nodes[j] = proofSiblings[i][j];
+                } else if (j == proofPathIndices[i]) {
+                    nodes[j] = hash;
+                } else {
+                    nodes[j] = proofSiblings[i][j - 1];
+                }
+            }
+
+            if (
+                nodes[0] == self.lastSubtrees[i][0] ||
+                nodes[4] == self.lastSubtrees[i][4]
+            ) {
+                self.lastSubtrees[i][proofPathIndices[i]] = hash;
+            }
+
+            hash = PoseidonT6.poseidon(nodes);
+        }
+
+        self.root = hash;
+    }
+
     /// @dev Removes a leaf from the tree.
     /// @param self: Tree data.
     /// @param leaf: Leaf to be removed.
@@ -110,7 +166,10 @@ library IncrementalQuinTree {
                 }
             }
 
-            if (nodes[0] == self.lastSubtrees[i][0] || nodes[4] == self.lastSubtrees[i][4]) {
+            if (
+                nodes[0] == self.lastSubtrees[i][0] ||
+                nodes[4] == self.lastSubtrees[i][4]
+            ) {
                 self.lastSubtrees[i][proofPathIndices[i]] = hash;
             }
 
@@ -132,9 +191,13 @@ library IncrementalQuinTree {
         uint256[4][] calldata proofSiblings,
         uint8[] calldata proofPathIndices
     ) private view returns (bool) {
-        require(leaf < SNARK_SCALAR_FIELD, "IncrementalQuinTree: leaf must be < SNARK_SCALAR_FIELD");
         require(
-            proofPathIndices.length == self.depth && proofSiblings.length == self.depth,
+            leaf < SNARK_SCALAR_FIELD,
+            "IncrementalQuinTree: leaf must be < SNARK_SCALAR_FIELD"
+        );
+        require(
+            proofPathIndices.length == self.depth &&
+                proofSiblings.length == self.depth,
             "IncrementalQuinTree: length of path is not correct"
         );
 
diff --git a/packages/incremental-merkle-tree.sol/contracts/test/IncrementalBinaryTreeTest.sol b/packages/incremental-merkle-tree.sol/contracts/test/IncrementalBinaryTreeTest.sol
index 1594e35..1f658d5 100644
--- a/packages/incremental-merkle-tree.sol/contracts/test/IncrementalBinaryTreeTest.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/test/IncrementalBinaryTreeTest.sol
@@ -9,6 +9,7 @@ contract IncrementalBinaryTreeTest {
 
     event TreeCreated(bytes32 id, uint8 depth);
     event LeafInserted(bytes32 indexed treeId, uint256 leaf, uint256 root);
+    event LeafUpdated(bytes32 indexed treeId, uint256 leaf, uint256 root);
     event LeafRemoved(bytes32 indexed treeId, uint256 leaf, uint256 root);
 
     mapping(bytes32 => IncrementalTreeData) public trees;
@@ -22,20 +23,42 @@ contract IncrementalBinaryTreeTest {
     }
 
     function insertLeaf(bytes32 _treeId, uint256 _leaf) external {
-        require(trees[_treeId].depth != 0, "BinaryTreeTest: tree does not exist");
+        require(
+            trees[_treeId].depth != 0,
+            "BinaryTreeTest: tree does not exist"
+        );
 
         trees[_treeId].insert(_leaf);
 
         emit LeafInserted(_treeId, _leaf, trees[_treeId].root);
     }
 
+    function updateLeaf(
+        bytes32 _treeId,
+        uint256 _leaf,
+        uint256[] calldata _proofSiblings,
+        uint8[] calldata _proofPathIndices
+    ) external {
+        require(
+            trees[_treeId].depth != 0,
+            "BinaryTreeTest: tree does not exist"
+        );
+
+        trees[_treeId].update(_leaf, _proofSiblings, _proofPathIndices);
+
+        emit LeafUpdated(_treeId, _leaf, trees[_treeId].root);
+    }
+
     function removeLeaf(
         bytes32 _treeId,
         uint256 _leaf,
         uint256[] calldata _proofSiblings,
         uint8[] calldata _proofPathIndices
     ) external {
-        require(trees[_treeId].depth != 0, "BinaryTreeTest: tree does not exist");
+        require(
+            trees[_treeId].depth != 0,
+            "BinaryTreeTest: tree does not exist"
+        );
 
         trees[_treeId].remove(_leaf, _proofSiblings, _proofPathIndices);
 
diff --git a/packages/incremental-merkle-tree.sol/contracts/test/IncrementalQuinTreeTest.sol b/packages/incremental-merkle-tree.sol/contracts/test/IncrementalQuinTreeTest.sol
index 62f7060..090af54 100644
--- a/packages/incremental-merkle-tree.sol/contracts/test/IncrementalQuinTreeTest.sol
+++ b/packages/incremental-merkle-tree.sol/contracts/test/IncrementalQuinTreeTest.sol
@@ -9,6 +9,7 @@ contract IncrementalQuinTreeTest {
 
     event TreeCreated(bytes32 id, uint8 depth);
     event LeafInserted(bytes32 indexed treeId, uint256 leaf, uint256 root);
+    event LeafUpdated(bytes32 indexed treeId, uint256 leaf, uint256 root);
     event LeafRemoved(bytes32 indexed treeId, uint256 leaf, uint256 root);
 
     mapping(bytes32 => IncrementalTreeData) public trees;
@@ -29,6 +30,19 @@ contract IncrementalQuinTreeTest {
         emit LeafInserted(_treeId, _leaf, trees[_treeId].root);
     }
 
+    function updateLeaf(
+        bytes32 _treeId,
+        uint256 _leaf,
+        uint256[4][] calldata _proofSiblings,
+        uint8[] calldata _proofPathIndices
+    ) external {
+        require(trees[_treeId].depth != 0, "QuinTreeTest: tree does not exist");
+
+        trees[_treeId].update(_leaf, _proofSiblings, _proofPathIndices);
+
+        emit LeafUpdated(_treeId, _leaf, trees[_treeId].root);
+    }
+
     function removeLeaf(
         bytes32 _treeId,
         uint256 _leaf,
diff --git a/yarn.lock b/yarn.lock
index fb3fdf0..5412021 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -8834,7 +8834,7 @@ __metadata:
   dependencies:
     bn.js: ^4.11.8
     ethereumjs-util: ^6.0.0
-  checksum: 03127d09960e5f8a44167463faf25b2894db2f746376dbb8195b789ed11762f93db9c574eaa7c498c400063508e9dfc1c80de2edf5f0e1406b25c87d860ff2f1
+  checksum: ae074be0bb012857ab5d3ae644d1163b908a48dd724b7d2567cfde309dc72222d460438f2411936a70dc949dc604ce1ef7118f7273bd525815579143c907e336
   languageName: node
   linkType: hard