diff --git a/src/mcp/server/stdio.py b/src/mcp/server/stdio.py
index e526bab56..332f809b7 100644
--- a/src/mcp/server/stdio.py
+++ b/src/mcp/server/stdio.py
@@ -17,6 +17,7 @@ async def run_server():
     ```
 """
 
+import os
 import sys
 from contextlib import asynccontextmanager
 from io import TextIOWrapper
@@ -39,9 +40,9 @@ async def stdio_server(stdin: anyio.AsyncFile[str] | None = None, stdout: anyio.
     # python is platform-dependent (Windows is particularly problematic), so we
     # re-wrap the underlying binary stream to ensure UTF-8.
     if not stdin:
-        stdin = anyio.wrap_file(TextIOWrapper(sys.stdin.buffer, encoding="utf-8"))
+        stdin = anyio.wrap_file(TextIOWrapper(os.fdopen(os.dup(sys.stdin.fileno()), "rb"), encoding="utf-8"))
     if not stdout:
-        stdout = anyio.wrap_file(TextIOWrapper(sys.stdout.buffer, encoding="utf-8"))
+        stdout = anyio.wrap_file(TextIOWrapper(os.fdopen(os.dup(sys.stdout.fileno()), "wb"), encoding="utf-8"))
 
     read_stream: MemoryObjectReceiveStream[SessionMessage | Exception]
     read_stream_writer: MemoryObjectSendStream[SessionMessage | Exception]