diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index 3134ddb6164c1e..9909a6dd63d4a0 100644
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -55,9 +55,24 @@
 import os
 from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, EINVAL, \
      ENOTCONN, ESHUTDOWN, EINTR, EISCONN, EBADF, ECONNABORTED, EPIPE, EAGAIN, \
-     errorcode, \
-     WSAEWOULDBLOCK, WSAENOTCONN, WSAEINPROGRESS, WSAEALREADY, WSAEISCONN, \
-     WSAECONNABORTED, WSAENOTCONN, WSAEBADF
+     errorcode
+
+if sys.platform[:3] == 'win':
+    # On Windows, handle the Windows error numbers
+    from errno import \
+        WSAEWOULDBLOCK, WSAENOTCONN, WSAEINPROGRESS, WSAEALREADY, WSAEISCONN, \
+        WSAECONNABORTED, WSAENOTCONN, WSAEBADF
+else:
+    # On Posix the error codes aren't duplicated, with different numbers
+    WSAEWOULDBLOCK = EWOULDBLOCK
+    WSAENOTCONN = ENOTCONN
+    WSAEINPROGRESS = EINPROGRESS
+    WSAEALREADY = EALREADY
+    WSAEISCONN = EISCONN
+    WSAECONNABORTED = ECONNABORTED
+    WSAENOTCONN = ENOTCONN
+    WSAEBADF = EBADF
+
 
 _DISCONNECTED = frozenset((ECONNRESET, ENOTCONN, ESHUTDOWN, ECONNABORTED, EPIPE,
                            EBADF, WSAENOTCONN, WSAECONNABORTED, WSAEBADF))