diff --git a/libs/partners/mistralai/langchain_mistralai/chat_models.py b/libs/partners/mistralai/langchain_mistralai/chat_models.py
index 71d9ef79841..bf5ca6b8673 100644
--- a/libs/partners/mistralai/langchain_mistralai/chat_models.py
+++ b/libs/partners/mistralai/langchain_mistralai/chat_models.py
@@ -42,8 +42,8 @@ from langchain_core.outputs import (
     ChatGenerationChunk,
     ChatResult,
 )
-from langchain_core.pydantic_v1 import root_validator
-from langchain_core.utils import get_from_dict_or_env
+from langchain_core.pydantic_v1 import SecretStr, root_validator
+from langchain_core.utils import convert_to_secret_str, get_from_dict_or_env
 
 # TODO: Remove 'type: ignore' once mistralai has stubs or py.typed marker.
 from mistralai.async_client import MistralAsyncClient  # type: ignore[import]
@@ -111,18 +111,11 @@ async def acompletion_with_retry(
 
     @retry_decorator
     async def _completion_with_retry(**kwargs: Any) -> Any:
-        client = MistralAsyncClient(
-            api_key=llm.mistral_api_key,
-            endpoint=llm.endpoint,
-            max_retries=llm.max_retries,
-            timeout=llm.timeout,
-            max_concurrent_requests=llm.max_concurrent_requests,
-        )
         stream = kwargs.pop("stream", False)
         if stream:
-            return client.chat_stream(**kwargs)
+            return llm.async_client.chat_stream(**kwargs)
         else:
-            return await client.chat(**kwargs)
+            return await llm.async_client.chat(**kwargs)
 
     return await _completion_with_retry(**kwargs)
 
@@ -163,8 +156,9 @@ def _convert_message_to_mistral_chat_message(
 class ChatMistralAI(BaseChatModel):
     """A chat model that uses the MistralAI API."""
 
-    client: Any  #: :meta private:
-    mistral_api_key: Optional[str] = None
+    client: MistralClient = None  #: :meta private:
+    async_client: MistralAsyncClient = None  #: :meta private:
+    mistral_api_key: Optional[SecretStr] = None
     endpoint: str = DEFAULT_MISTRAL_ENDPOINT
     max_retries: int = 5
     timeout: int = 120
@@ -224,15 +218,24 @@ class ChatMistralAI(BaseChatModel):
                 "Please install it with `pip install mistralai`"
             )
 
-        values["mistral_api_key"] = get_from_dict_or_env(
-            values, "mistral_api_key", "MISTRAL_API_KEY", default=""
+        values["mistral_api_key"] = convert_to_secret_str(
+            get_from_dict_or_env(
+                values, "mistral_api_key", "MISTRAL_API_KEY", default=""
+            )
         )
         values["client"] = MistralClient(
-            api_key=values["mistral_api_key"],
+            api_key=values["mistral_api_key"].get_secret_value(),
             endpoint=values["endpoint"],
             max_retries=values["max_retries"],
             timeout=values["timeout"],
         )
+        values["async_client"] = MistralAsyncClient(
+            api_key=values["mistral_api_key"].get_secret_value(),
+            endpoint=values["endpoint"],
+            max_retries=values["max_retries"],
+            timeout=values["timeout"],
+            max_concurrent_requests=values["max_concurrent_requests"],
+        )
 
         if values["temperature"] is not None and not 0 <= values["temperature"] <= 1:
             raise ValueError("temperature must be in the range [0.0, 1.0]")