diff --git a/psycopg/config.h b/psycopg/config.h
index 708f0a89..551cfe48 100644
--- a/psycopg/config.h
+++ b/psycopg/config.h
@@ -51,6 +51,10 @@ extern HIDDEN int psycopg_debug_enabled;
 #else /* !__GNUC__ or __APPLE__ */
 #ifdef PSYCOPG_DEBUG
 #include <stdarg.h>
+#ifdef _WIN32
+#include <process.h>
+#define getpid _getpid
+#endif
 static void Dprintf(const char *fmt, ...)
 {
     va_list ap;