diff --git a/dlls/kernel32/debugger.c b/dlls/kernel32/debugger.c
index e9b5992e7ac..3abffdf51ba 100644
--- a/dlls/kernel32/debugger.c
+++ b/dlls/kernel32/debugger.c
@@ -253,7 +253,7 @@ void WINAPI OutputDebugStringA( LPCSTR str )
     }
     SERVER_END_REQ;
 
-    WARN("%s\n", str);
+    WARN("%s\n", debugstr_a(str));
 
     /* send string to a system-wide monitor */
     /* FIXME should only send to monitor if no debuggers are attached */