diff --git a/src/compiler/tsbuild.ts b/src/compiler/tsbuild.ts
index 695b9f8622f7d..5c9c7086db872 100644
--- a/src/compiler/tsbuild.ts
+++ b/src/compiler/tsbuild.ts
@@ -488,6 +488,7 @@ namespace ts {
         }
 
         if (watch) {
+            builder.buildAllProjects();
             builder.startWatching();
             return undefined;
         }