diff --git a/libs/partners/mistralai/langchain_mistralai/chat_models.py b/libs/partners/mistralai/langchain_mistralai/chat_models.py
index 85924a714543c..aed0f70542786 100644
--- a/libs/partners/mistralai/langchain_mistralai/chat_models.py
+++ b/libs/partners/mistralai/langchain_mistralai/chat_models.py
@@ -353,7 +353,9 @@ def _convert_message_to_mistral_chat_message(
             "role": "tool",
             "content": message.content,
             "name": message.name,
-            "tool_call_id": message.tool_call_id,
+            "tool_call_id": _convert_tool_call_id_to_mistral_compatible(
+                message.tool_call_id
+            ),
         }
     else:
         raise ValueError(f"Got unknown type {message}")