diff --git a/contracts/AccountFactory.sol b/contracts/AccountFactory.sol
index 86cbf10..7ec4aa0 100644
--- a/contracts/AccountFactory.sol
+++ b/contracts/AccountFactory.sol
@@ -118,6 +118,9 @@ contract AccountFactory is Ownable2Step {
         bytes32 salt,
         bytes calldata initializer
     ) external payable returns (address accountAddress) {
+        if (saltToAccount[salt] != address(0)) {
+            revert Errors.ALREADY_CREATED();
+        }
         // Check that the initializer is not empty
         if (initializer.length < 4) {
             revert Errors.INVALID_INITIALIZER();
diff --git a/contracts/libraries/Errors.sol b/contracts/libraries/Errors.sol
index 036e442..d96bfc5 100644
--- a/contracts/libraries/Errors.sol
+++ b/contracts/libraries/Errors.sol
@@ -100,8 +100,9 @@ library Errors {
 
     error DEPLOYMENT_FAILED(); // 0x0f02d218
     error INITIALIZATION_FAILED(); // 0x5b101091
-    error INVALID_INITIALIZER();
-    error INVALID_SALT();
+    error INVALID_INITIALIZER(); // 0x350366d7
+    error INVALID_SALT(); // 0x8b3152e6
+    error ALREADY_CREATED(); // 0x26ebf2e8
 
     /*//////////////////////////////////////////////////////////////
                             PAYMASTER
diff --git a/test/deployments/deployer.test.ts b/test/deployments/deployer.test.ts
index bbd7e5e..e75f61e 100644
--- a/test/deployments/deployer.test.ts
+++ b/test/deployments/deployer.test.ts
@@ -6,7 +6,7 @@
 import { expect } from 'chai';
 import type { ec } from 'elliptic';
 import type { BytesLike, HDNodeWallet } from 'ethers';
-import { getAddress, hexlify, parseEther, randomBytes } from 'ethers';
+import { getAddress, hexlify, keccak256, parseEther, randomBytes } from 'ethers';
 import * as hre from 'hardhat';
 import type { Contract, Wallet } from 'zksync-ethers';
 import { Provider } from 'zksync-ethers';
@@ -109,12 +109,22 @@ describe('AGW Contracts - Deployer class tests', () => {
         });
 
         it('should not deploy an account with an empty initializer', async () => {
-            await expect(deployer.account(wallet, factory, eoaValidator, { initializer: '0x' }))
+            const pk = randomBytes(32);
+            const wallet = getWallet(hre, hexlify(pk));
+            await expect(deployer.account(wallet, factory, eoaValidator, { 
+                salt: keccak256(wallet.address),
+                initializer: '0x' 
+            }))
             .to.be.revertedWithCustomError(factory, "INVALID_INITIALIZER");
         });
 
         it('should not deploy an account with an invalid initializer selector', async () => {
-            await expect(deployer.account(wallet, factory, eoaValidator, { initializer: '0xabababab' }))
+            const pk = randomBytes(32);
+            const wallet = getWallet(hre, hexlify(pk));
+            await expect(deployer.account(wallet, factory, eoaValidator, { 
+                salt: keccak256(wallet.address), 
+                initializer: '0xabababab' 
+            }))
             .to.be.revertedWithCustomError(factory, "INVALID_INITIALIZER");
         });