diff --git a/test/parallel/test-fs-mkdir.js b/test/parallel/test-fs-mkdir.js
index f5fecbe1572aaf..d07aab53769299 100644
--- a/test/parallel/test-fs-mkdir.js
+++ b/test/parallel/test-fs-mkdir.js
@@ -177,6 +177,32 @@ if (common.isMainThread && (common.isLinux || common.isOSX)) {
   });
 }
 
+// mkdirSync and mkdir require options.recursive to be a boolean.
+// Anything else generates an error.
+{
+  const pathname = path.join(tmpdir.path, nextdir());
+  ['', 1, {}, [], null, Symbol('test'), () => {}].forEach((recursive) => {
+    common.expectsError(
+      () => fs.mkdir(pathname, { recursive }, common.mustNotCall()),
+      {
+        code: 'ERR_INVALID_ARG_TYPE',
+        type: TypeError,
+        message: 'The "recursive" argument must be of type boolean. Received ' +
+          `type ${typeof recursive}`
+      }
+    );
+    common.expectsError(
+      () => fs.mkdirSync(pathname, { recursive }),
+      {
+        code: 'ERR_INVALID_ARG_TYPE',
+        type: TypeError,
+        message: 'The "recursive" argument must be of type boolean. Received ' +
+          `type ${typeof recursive}`
+      }
+    );
+  });
+}
+
 // Keep the event loop alive so the async mkdir() requests
 // have a chance to run (since they don't ref the event loop).
 process.nextTick(() => {});
diff --git a/test/parallel/test-fs-promises.js b/test/parallel/test-fs-promises.js
index bcfaaf3890d377..714f1db05d5494 100644
--- a/test/parallel/test-fs-promises.js
+++ b/test/parallel/test-fs-promises.js
@@ -211,6 +211,22 @@ function verifyStatObject(stat) {
     assert.deepStrictEqual(list, ['baz2.js', 'dir']);
     await rmdir(newdir);
 
+    // mkdir when options is number.
+    {
+      const dir = path.join(tmpDir, nextdir());
+      await mkdir(dir, 777);
+      stats = await stat(dir);
+      assert(stats.isDirectory());
+    }
+
+    // mkdir when options is string.
+    {
+      const dir = path.join(tmpDir, nextdir());
+      await mkdir(dir, '777');
+      stats = await stat(dir);
+      assert(stats.isDirectory());
+    }
+
     // mkdirp when folder does not yet exist.
     {
       const dir = path.join(tmpDir, nextdir(), nextdir());
@@ -250,6 +266,24 @@ function verifyStatObject(stat) {
       assert(stats.isDirectory());
     }
 
+    // mkdirp require recursive option to be a boolean.
+    // Anything else generates an error.
+    {
+      const dir = path.join(tmpDir, nextdir(), nextdir());
+      ['', 1, {}, [], null, Symbol('test'), () => {}].forEach((recursive) => {
+        assert.rejects(
+          // mkdir() expects to get a boolean value for options.recursive.
+          async () => mkdir(dir, { recursive }),
+          {
+            code: 'ERR_INVALID_ARG_TYPE',
+            name: 'TypeError [ERR_INVALID_ARG_TYPE]',
+            message: 'The "recursive" argument must be of type boolean. ' +
+              `Received type ${typeof recursive}`
+          }
+        );
+      });
+    }
+
     await mkdtemp(path.resolve(tmpDir, 'FOO'));
     assert.rejects(
       // mkdtemp() expects to get a string prefix.