diff --git a/multiversx_sdk_cli/cosign_transaction.py b/multiversx_sdk_cli/cosign_transaction.py
index 26aada47..30a3ec79 100644
--- a/multiversx_sdk_cli/cosign_transaction.py
+++ b/multiversx_sdk_cli/cosign_transaction.py
@@ -1,6 +1,8 @@
 from typing import Any, Dict
 
 import requests
+from multiversx_sdk_network_providers.transactions import \
+    transaction_to_dictionary
 
 from multiversx_sdk_cli.errors import GuardianServiceError
 from multiversx_sdk_cli.interfaces import ITransaction
@@ -9,7 +11,7 @@
 def cosign_transaction(transaction: ITransaction, service_url: str, guardian_code: str) -> ITransaction:
     payload = {
         "code": f"{guardian_code}",
-        "transaction": transaction.__dict__
+        "transaction": transaction_to_dictionary(transaction)
     }
 
     url = f"{service_url}/sign-transaction"