diff --git a/README.md b/README.md
index 4710e947..00abc21a 100644
--- a/README.md
+++ b/README.md
@@ -569,6 +569,8 @@ A comma separated list of allowed issue types. Only issues with a matching type
 
 If unset (or an empty string), this option will not alter the stale workflow.
 
+This option does not affect PRs.
+
 Default value: unset
 
 ### Usage
diff --git a/__tests__/only-issue-types.spec.ts b/__tests__/only-issue-types.spec.ts
index c91d5658..41950480 100644
--- a/__tests__/only-issue-types.spec.ts
+++ b/__tests__/only-issue-types.spec.ts
@@ -122,4 +122,37 @@ describe('only-issue-types option', () => {
       'A feature'
     ]);
   });
+
+  test('should ignore onlyIssueTypes filter when item is a pull request', async () => {
+    const opts: IIssuesProcessorOptions = {
+      ...DefaultProcessorOptions,
+      onlyIssueTypes: 'bug'
+    };
+    const TestIssueList: Issue[] = [
+      generateIssue(
+        opts,
+        1,
+        'A pull request',
+        '2020-01-01T17:00:00Z',
+        '2020-01-01T17:00:00Z',
+        false,
+        true, // isPullRequest = true
+        [],
+        false,
+        false,
+        undefined,
+        [],
+        undefined // pull requests do not have an issue_type
+      )
+    ];
+    const processor = new IssuesProcessorMock(
+      opts,
+      alwaysFalseStateMock,
+      async p => (p === 1 ? TestIssueList : []),
+      async () => [],
+      async () => new Date().toDateString()
+    );
+    await processor.processIssues(1);
+    expect(processor.staleIssues.map(i => i.title)).toEqual(['A pull request']);
+  });
 });
diff --git a/dist/index.js b/dist/index.js
index bf156344..171c5d13 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -513,7 +513,7 @@ class IssuesProcessor {
                 IssuesProcessor._endIssueProcessing(issue);
                 return; // If the issue has an 'include-only-assigned' option set, process only issues with nonempty assignees list
             }
-            if (this.options.onlyIssueTypes) {
+            if (this.options.onlyIssueTypes && !issue.isPullRequest) {
                 const allowedTypes = this.options.onlyIssueTypes
                     .split(',')
                     .map(t => t.trim().toLowerCase())
diff --git a/src/classes/issues-processor.ts b/src/classes/issues-processor.ts
index c4e444fd..7933e449 100644
--- a/src/classes/issues-processor.ts
+++ b/src/classes/issues-processor.ts
@@ -252,7 +252,7 @@ export class IssuesProcessor {
       return; // If the issue has an 'include-only-assigned' option set, process only issues with nonempty assignees list
     }
 
-    if (this.options.onlyIssueTypes) {
+    if (this.options.onlyIssueTypes && !issue.isPullRequest) {
       const allowedTypes = this.options.onlyIssueTypes
         .split(',')
         .map(t => t.trim().toLowerCase())