diff --git a/config.w32 b/config.w32
index e8f8f9b..d72697a 100644
--- a/config.w32
+++ b/config.w32
@@ -14,6 +14,7 @@ var DECIMAL_EXT_DEP_LIB_STATIC ="libmpdec_a.lib";
 ARG_WITH("decimal", "for decimal support", "no");
 
 if (PHP_DECIMAL == "yes") {
+    ADD_EXTENSION_DEP("decimal", "json");
     var setup_ok = false;
     var libmpdec_shared = false;