diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index a0bccd57247b..c3e81a1a490b 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -651,7 +651,7 @@
   "google-cloud-parallelstore-v1+FILLER": "0.0.0",
   "google-cloud-parallelstore-v1beta": "0.14.0",
   "google-cloud-parallelstore-v1beta+FILLER": "0.0.0",
-  "google-cloud-parameter_manager": "0.3.0",
+  "google-cloud-parameter_manager": "0.4.0",
   "google-cloud-parameter_manager+FILLER": "0.0.0",
   "google-cloud-parameter_manager-v1": "0.8.0",
   "google-cloud-parameter_manager-v1+FILLER": "0.0.0",
diff --git a/google-cloud-parameter_manager/CHANGELOG.md b/google-cloud-parameter_manager/CHANGELOG.md
index 7d0f4284c738..9abea4800d5d 100644
--- a/google-cloud-parameter_manager/CHANGELOG.md
+++ b/google-cloud-parameter_manager/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+### 0.4.0 (2026-07-16)
+
+#### Features
+
+* Release GA version 1.0.0 ([#34791](https://github.com/googleapis/google-cloud-ruby/issues/34791)) 
+
 ### 0.3.0 (2026-06-11)
 
 #### Features
@@ -37,4 +43,3 @@
 * Initial generation of google-cloud-parameter_manager ([#29266](https://github.com/googleapis/google-cloud-ruby/issues/29266)) 
 
 ## Release History
-
diff --git a/google-cloud-parameter_manager/lib/google/cloud/parameter_manager/version.rb b/google-cloud-parameter_manager/lib/google/cloud/parameter_manager/version.rb
index c775f360b24d..1e9d27be481d 100644
--- a/google-cloud-parameter_manager/lib/google/cloud/parameter_manager/version.rb
+++ b/google-cloud-parameter_manager/lib/google/cloud/parameter_manager/version.rb
@@ -20,7 +20,7 @@
 module Google
   module Cloud
     module ParameterManager
-      VERSION = "0.3.0"
+      VERSION = "0.4.0"
     end
   end
 end