diff --git a/examples/mtdpart/mtdpart_main.c b/examples/mtdpart/mtdpart_main.c
index a54c7828c..d1fa7aef9 100644
--- a/examples/mtdpart/mtdpart_main.c
+++ b/examples/mtdpart/mtdpart_main.c
@@ -95,7 +95,7 @@
 
 #endif
 
-#ifdef CONFIG_EXAMPLES_MTDPART_NPARTITIONS
+#ifndef CONFIG_EXAMPLES_MTDPART_NPARTITIONS
 #  define CONFIG_EXAMPLES_MTDPART_NPARTITIONS 3
 #endif