diff --git a/src/utils/stellar.ts b/src/utils/stellar.ts
index 8d4c4ec..86fa44b 100644
--- a/src/utils/stellar.ts
+++ b/src/utils/stellar.ts
@@ -119,7 +119,11 @@ export const StellarUtils = {
           ? Networks.FUTURENET
           : Networks.TESTNET;
 
-    const asset = assetCode === 'XLM' ? Asset.native() : new Asset(assetCode, issuer as string);
+    if (assetCode !== 'XLM' && (!issuer || !ValidationUtils.isValidStellarAddress(issuer))) {
+      throw new Error(`A valid issuer is required for non-native asset payments: ${assetCode}`);
+    }
+
+    const asset = assetCode === 'XLM' ? Asset.native() : new Asset(assetCode, issuer);
 
     // We use a dummy sequence number because the actual submission will be handled later
     // or by a signer that manages sequence numbers.
diff --git a/tests/utils/stellar.test.ts b/tests/utils/stellar.test.ts
index f53ba87..95e1568 100644
--- a/tests/utils/stellar.test.ts
+++ b/tests/utils/stellar.test.ts
@@ -92,6 +92,31 @@ describe('StellarUtils', () => {
       expect(parseFloat(operation.amount)).toBe(parseFloat(params.amount));
     });
 
+    it('should throw a clear error when a non-native asset issuer is missing', async () => {
+      await expect(
+        StellarUtils.buildPaymentXdr({
+          source: validAccountId,
+          destination: validAccountId,
+          amount: '1.5',
+          assetCode: 'USDC',
+          network: 'testnet',
+        }),
+      ).rejects.toThrow('A valid issuer is required for non-native asset payments: USDC');
+    });
+
+    it('should throw a clear error when a non-native asset issuer is invalid', async () => {
+      await expect(
+        StellarUtils.buildPaymentXdr({
+          source: validAccountId,
+          destination: validAccountId,
+          amount: '1.5',
+          assetCode: 'USDC',
+          issuer: invalidAccountId,
+          network: 'testnet',
+        }),
+      ).rejects.toThrow('A valid issuer is required for non-native asset payments: USDC');
+    });
+
     it('should throw when parsing invalid XDR', () => {
       expect(() => StellarUtils.parseXdrTransaction('invalid-xdr')).toThrow(/Failed to parse XDR/);
     });