diff --git a/json_inttypes.h b/json_inttypes.h
index a33a31f..4cc5fc1 100644
--- a/json_inttypes.h
+++ b/json_inttypes.h
@@ -29,7 +29,7 @@ typedef unsigned __int64 uint64_t;
 
 #endif
 
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) && !defined(ssize_t)
 #include <BaseTsd.h>
 typedef SSIZE_T ssize_t;
 #endif
diff --git a/json_object_private.h b/json_object_private.h
index e143b46..f81af88 100644
--- a/json_object_private.h
+++ b/json_object_private.h
@@ -28,7 +28,7 @@ struct json_object;
 #include <unistd.h>
 #endif /* HAVE_UNISTD_H */
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && !defined(ssize_t)
 #include <BaseTsd.h>
 typedef SSIZE_T ssize_t;
 #endif