diff --git a/Python/import.c b/Python/import.c
index d1da0015824..67cd31e6ddc 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -40,6 +40,10 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #define SEP ':'
 #endif
 
+#ifdef MSDOS
+#define SEP '\\'
+#endif
+
 #ifndef SEP
 #define SEP '/'
 #endif