diff --git a/cloudprober/package.json b/cloudprober/package.json
index d466341..c6e857a 100644
--- a/cloudprober/package.json
+++ b/cloudprober/package.json
@@ -8,7 +8,7 @@
     "argparse": "^2.0.0",
     "bluebird": "^3.5.2",
     "google-auth-library": "^8.0.0",
-    "google-protobuf": "^3.6.1",
+    "google-protobuf": "^4.0.0",
     "grpc": "^1.15.1",
     "grpc-tools": "^1.6.6"
   }
diff --git a/package.json b/package.json
index 89e0474..f37ec6b 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
     "c8": "^7.7.2",
     "google-auth-library": "^8.0.0",
     "google-gax": "^3.0.0",
-    "google-protobuf": "^3.17.1",
+    "google-protobuf": "^4.0.0",
     "grpc": "^1.24.10",
     "grpc-tools": "^1.11.1",
     "gts": "^3.1.0",