diff --git a/packages/zevm-app-contracts/contracts/xp-nft/xpNFT.sol b/packages/zevm-app-contracts/contracts/xp-nft/xpNFT.sol
index 9b1477b..a195535 100644
--- a/packages/zevm-app-contracts/contracts/xp-nft/xpNFT.sol
+++ b/packages/zevm-app-contracts/contracts/xp-nft/xpNFT.sol
@@ -23,6 +23,7 @@ contract ZetaXP is ERC721Upgradeable, OwnableUpgradeable {
     mapping(uint256 => uint256) public lastUpdateTimestampByTokenId;
     mapping(uint256 => uint256) public signedUpByTokenId;
     mapping(uint256 => bytes32) public tagByTokenId;
+    mapping(address => mapping(bytes32 => uint256)) public tokenByUserTag;
 
     // Base URL for NFT images
     string public baseTokenURI;
@@ -40,6 +41,7 @@ contract ZetaXP is ERC721Upgradeable, OwnableUpgradeable {
     error LengthMismatch();
     error TransferNotAllowed();
     error OutdatedSignature();
+    error TagAlreadyHoldByUser();
 
     function initialize(
         string memory name,
@@ -122,6 +124,8 @@ contract ZetaXP is ERC721Upgradeable, OwnableUpgradeable {
         _verify(tokenId, updateData);
         lastUpdateTimestampByTokenId[tokenId] = updateData.sigTimestamp;
         signedUpByTokenId[tokenId] = updateData.signedUp;
+        tagByTokenId[tokenId] = updateData.tag;
+        tokenByUserTag[updateData.to][updateData.tag] = tokenId;
     }
 
     // External mint function with auto-incremented token ID
@@ -129,6 +133,7 @@ contract ZetaXP is ERC721Upgradeable, OwnableUpgradeable {
         uint256 newTokenId = _currentTokenId;
         _mint(mintData.to, newTokenId);
 
+        if (tokenByUserTag[mintData.to][mintData.tag] != 0) revert TagAlreadyHoldByUser();
         _updateNFT(newTokenId, mintData);
 
         emit NFTMinted(mintData.to, newTokenId, mintData.tag);
@@ -140,6 +145,7 @@ contract ZetaXP is ERC721Upgradeable, OwnableUpgradeable {
     function updateNFT(uint256 tokenId, UpdateData memory updateData) external {
         address owner = ownerOf(tokenId);
         updateData.to = owner;
+        if (tokenByUserTag[owner][updateData.tag] != tokenId) revert TagAlreadyHoldByUser();
         _updateNFT(tokenId, updateData);
 
         emit NFTUpdated(owner, tokenId, updateData.tag);
diff --git a/packages/zevm-app-contracts/test/xp-nft/xp-nft.ts b/packages/zevm-app-contracts/test/xp-nft/xp-nft.ts
index 27fffd7..8cc3b77 100644
--- a/packages/zevm-app-contracts/test/xp-nft/xp-nft.ts
+++ b/packages/zevm-app-contracts/test/xp-nft/xp-nft.ts
@@ -175,7 +175,11 @@ describe("XP NFT Contract test", () => {
     await expect(url).to.be.eq(`${ZETA_BASE_URL}v2/`);
 
     {
-      const sampleNFT2 = { ...sampleNFT, tokenId: 2 };
+      const sampleNFT2 = {
+        ...sampleNFT,
+        tag: ethers.utils.keccak256(ethers.utils.defaultAbiCoder.encode(["string"], ["XP_NFT2"])),
+        tokenId: 2,
+      };
       const currentBlock = await ethers.provider.getBlock("latest");
       const sigTimestamp = currentBlock.timestamp;
 
@@ -250,4 +254,64 @@ describe("XP NFT Contract test", () => {
     const version2 = await zetaXPV2.version();
     await expect(version2).to.be.eq("2.0.0");
   });
+
+  it("Should revert if user already have the tag", async () => {
+    {
+      const currentBlock = await ethers.provider.getBlock("latest");
+      const sigTimestamp = currentBlock.timestamp;
+
+      const signature = await getSignature(signer, sigTimestamp, sampleNFT.to, sampleNFT);
+
+      const nftParams: UpdateParam = {
+        ...sampleNFT,
+        sigTimestamp,
+        signature,
+      } as UpdateParam;
+
+      await zetaXP.mintNFT(nftParams);
+    }
+
+    {
+      const sampleNFT2 = {
+        ...sampleNFT,
+        tokenId: 2,
+      };
+      const currentBlock = await ethers.provider.getBlock("latest");
+      const sigTimestamp = currentBlock.timestamp;
+
+      const signature = await getSignature(signer, sigTimestamp, user.address, sampleNFT2);
+
+      const nftParams: UpdateParam = {
+        ...sampleNFT2,
+        sigTimestamp,
+        signature,
+      } as UpdateParam;
+
+      const tx = zetaXP.mintNFT(nftParams);
+      await expect(tx).to.be.revertedWith("TagAlreadyHoldByUser");
+    }
+  });
+
+  it("Should query by tag and by user", async () => {
+    const currentBlock = await ethers.provider.getBlock("latest");
+    const sigTimestamp = currentBlock.timestamp;
+
+    const signature = await getSignature(signer, sigTimestamp, sampleNFT.to, sampleNFT);
+
+    const nftParams: UpdateParam = {
+      ...sampleNFT,
+      sigTimestamp,
+      signature,
+    } as UpdateParam;
+
+    const tx = await zetaXP.mintNFT(nftParams);
+    const receipt = await tx.wait();
+    const tokenId = getTokenIdFromRecipient(receipt);
+
+    const queriedTokenId = await zetaXP.tokenByUserTag(sampleNFT.to, sampleNFT.tag);
+    await expect(queriedTokenId).to.be.eq(tokenId);
+
+    const queriedTag = await zetaXP.tagByTokenId(tokenId);
+    await expect(queriedTag).to.be.eq(sampleNFT.tag);
+  });
 });