diff --git a/config.m4 b/config.m4
index 356a1df..9aaa3e9 100644
--- a/config.m4
+++ b/config.m4
@@ -34,6 +34,7 @@ if test "$PHP_RDKAFKA" != "no"; then
 
   PHP_CHECK_LIBRARY($LIBNAME,$LIBSYMBOL,
   [
+    PHP_ADD_INCLUDE($RDKAFKA_DIR/include)
     PHP_ADD_LIBRARY_WITH_PATH($LIBNAME, $RDKAFKA_DIR/$PHP_LIBDIR, RDKAFKA_SHARED_LIBADD)
     AC_DEFINE(HAVE_RDKAFKALIB,1,[ ])
   ],[