diff --git a/asset-transfer-basic/chaincode-javascript/lib/assetTransfer.js b/asset-transfer-basic/chaincode-javascript/lib/assetTransfer.js
index 821e413a..a1a27aa4 100644
--- a/asset-transfer-basic/chaincode-javascript/lib/assetTransfer.js
+++ b/asset-transfer-basic/chaincode-javascript/lib/assetTransfer.js
@@ -65,6 +65,11 @@ class AssetTransfer extends Contract {
 
     // CreateAsset issues a new asset to the world state with given details.
     async CreateAsset(ctx, id, color, size, owner, appraisedValue) {
+        const exists = await this.AssetExists(ctx, id);
+        if (exists) {
+            throw new Error(`The asset ${id} already exists`);
+        }
+
         const asset = {
             ID: id,
             Color: color,
diff --git a/asset-transfer-basic/chaincode-typescript/src/assetTransfer.ts b/asset-transfer-basic/chaincode-typescript/src/assetTransfer.ts
index b21f12ec..55b19b77 100644
--- a/asset-transfer-basic/chaincode-typescript/src/assetTransfer.ts
+++ b/asset-transfer-basic/chaincode-typescript/src/assetTransfer.ts
@@ -65,6 +65,11 @@ export class AssetTransferContract extends Contract {
     // CreateAsset issues a new asset to the world state with given details.
     @Transaction()
     public async CreateAsset(ctx: Context, id: string, color: string, size: number, owner: string, appraisedValue: number): Promise<void> {
+        const exists = await this.AssetExists(ctx, id);
+        if (exists) {
+            throw new Error(`The asset ${id} already exists`);
+        }
+
         const asset = {
             ID: id,
             Color: color,