diff --git a/lib/helpers.js b/lib/helpers.js
index 927e42e1..c109f486 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -49,7 +49,8 @@ class Helpers {
             let options = {
                 cwd: projectPath
             };
-            yield exec.exec('npm', ['ci'], options);
+            const useYarn = yield Helpers.isFileExists(path.join(projectPath, 'yarn.lock'));
+            yield (useYarn ? exec.exec('yarn', ['install'], options) : exec.exec('npm', ['ci'], options));
         });
     }
     static getLocalNgExecPath(baseDir) {
diff --git a/src/helpers.ts b/src/helpers.ts
index efbf3b3a..17c97566 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -34,7 +34,9 @@ export class Helpers {
         let options: ExecOptions = { 
             cwd: projectPath
         };
-        await exec.exec('npm',['ci'], options);
+
+        const useYarn = await Helpers.isFileExists(path.join(projectPath, 'yarn.lock'));
+        await (useYarn? exec.exec('yarn',['install'], options) : exec.exec('npm',['ci'], options));
     }
 
     public static getLocalNgExecPath(baseDir:string){