diff --git a/src/ncp/ncp_base.cpp b/src/ncp/ncp_base.cpp
index 9b96625f6..9e1b784ea 100644
--- a/src/ncp/ncp_base.cpp
+++ b/src/ncp/ncp_base.cpp
@@ -3187,7 +3187,7 @@ ThreadError NcpBase::SetPropertyHandler_NET_ROLE(uint8_t header, spinel_prop_key
         switch (i)
         {
         case SPINEL_NET_ROLE_DETACHED:
-            errorCode = kThreadError_InvalidArgs;
+            errorCode = otBecomeDetached(mInstance);
             break;
 
         case SPINEL_NET_ROLE_ROUTER: