diff --git a/libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_NRF51822/nordic_global.h b/libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_NRF51822/nordic_global.h
index 1370887d00..46235d4f5c 100644
--- a/libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_NRF51822/nordic_global.h
+++ b/libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_NRF51822/nordic_global.h
@@ -4,8 +4,14 @@
 /* There are no global defines in mbed, so we need to define */
 /* mandatory conditional compilation flags here              */
 //#define NRF51
+#ifndef	DEBUG_NRF_USER
 #define DEBUG_NRF_USER
+#endif
+#ifndef	BLE_STACK_SUPPORT_REQD
 #define BLE_STACK_SUPPORT_REQD
+#endif
+#ifndef	BOARD_PCA10001
 #define BOARD_PCA10001
+#endif
 
 #endif