diff --git a/node-radius/radius.d.ts b/node-radius/radius.d.ts
index cb6be029dd..b1079fafdc 100644
--- a/node-radius/radius.d.ts
+++ b/node-radius/radius.d.ts
@@ -36,9 +36,9 @@ declare module "radius" {
      * 
      * @param path Can be either a path to a file or a directory.
      **/
-    export function add_dictionary(path:string);
+    export function add_dictionary(path:string): void;
 
-    export function unload_dictionaries();
+    export function unload_dictionaries(): void;