diff --git a/include/grgsm/api.h b/include/grgsm/api.h
index a5684b4..cfe13b1 100644
--- a/include/grgsm/api.h
+++ b/include/grgsm/api.h
@@ -25,7 +25,7 @@
 
 #include <gnuradio/attributes.h>
 
-#ifdef gnuradio_gsm_EXPORTS
+#ifdef grgsm_EXPORTS
 #  define GRGSM_API __GR_ATTR_EXPORT
 #else
 #  define GRGSM_API __GR_ATTR_IMPORT