diff --git a/lib/services/codebuild.js b/lib/services/codebuild.js
index 8126527a..30ef6443 100644
--- a/lib/services/codebuild.js
+++ b/lib/services/codebuild.js
@@ -26,7 +26,10 @@ module.exports = {
       return git.branch()
     }
     function detectPRNumber() {
-      if (process.env.CODEBUILD_WEBHOOK_HEAD_REF) {
+      if (
+        process.env.CODEBUILD_WEBHOOK_HEAD_REF &&
+        process.env.CODEBUILD_SOURCE_VERSION.startsWith('pr/')
+      ) {
         return process.env.CODEBUILD_SOURCE_VERSION.replace(/^pr\//, '')
       }
       return undefined
diff --git a/test/services/codebuild.test.js b/test/services/codebuild.test.js
index 5bf510c0..82518f46 100644
--- a/test/services/codebuild.test.js
+++ b/test/services/codebuild.test.js
@@ -55,7 +55,7 @@ describe('AWS CodeBuild Provider', function() {
     })
   })
 
-  it('Test build triggered via Github Webhook', function() {
+  it('Test PR build triggered via Github Webhook', function() {
     process.env.CODEBUILD_WEBHOOK_HEAD_REF = 'refs/heads/master'
     expect(codebuild.configuration()).toEqual({
       service: 'codebuild',
@@ -68,6 +68,21 @@ describe('AWS CodeBuild Provider', function() {
     })
   })
 
+  it('Test non-PR build triggered via Github Webhook', function() {
+    process.env.CODEBUILD_WEBHOOK_HEAD_REF = 'refs/heads/master'
+    process.env.CODEBUILD_SOURCE_VERSION =
+      '39ec2418eca4c539d765574a1c68f3bd77e8c549'
+    expect(codebuild.configuration()).toEqual({
+      service: 'codebuild',
+      build: 'my-project:e016b9d9-f2c8-4749-8373-7ca673b6d969',
+      job: 'my-project:e016b9d9-f2c8-4749-8373-7ca673b6d969',
+      commit: '39ec2418eca4c539d765574a1c68f3bd77e8c549',
+      branch: 'master',
+      pr: undefined,
+      slug: 'my-org/my-project',
+    })
+  })
+
   it('throws if slug cannot be detected', function() {
     process.env.CODEBUILD_RESOLVED_SOURCE_VERSION =
       '39ec2418eca4c539d765574a1c68f3bd77e8c549'