diff --git a/lib/fs.js b/lib/fs.js
index 1ea70ff192d6dd..fbc985a2678ddb 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -3571,7 +3571,9 @@ function mkdtemp(prefix, options, callback) {
   if (h !== null && vfsResult(h.mkdtemp(prefix, typeof options === 'function' ? undefined : options), callback)) return;
 
   options = getOptions(options);
-
+  if (BufferIsBuffer(prefix)) {
+    options = { ...options, encoding: 'buffer' };
+  }
   prefix = getValidatedPath(prefix, 'prefix');
   warnOnNonPortableTemplate(prefix);
 
@@ -3594,7 +3596,9 @@ function mkdtempSync(prefix, options) {
   }
 
   options = getOptions(options);
-
+  if (BufferIsBuffer(prefix)) {
+    options = { ...options, encoding: 'buffer' };
+  }
   prefix = getValidatedPath(prefix, 'prefix');
   warnOnNonPortableTemplate(prefix);
   return binding.mkdtemp(prefix, options.encoding);
@@ -3610,7 +3614,9 @@ function mkdtempSync(prefix, options) {
  */
 function mkdtempDisposableSync(prefix, options) {
   options = getOptions(options);
-
+  if (BufferIsBuffer(prefix)) {
+    options = { ...options, encoding: 'buffer' };
+  }
   prefix = getValidatedPath(prefix, 'prefix');
   warnOnNonPortableTemplate(prefix);
 
diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
index 3e336024a15a3c..2208864556c8aa 100644
--- a/lib/internal/fs/promises.js
+++ b/lib/internal/fs/promises.js
@@ -2024,9 +2024,10 @@ async function mkdtemp(prefix, options) {
     const promise = h.mkdtemp(prefix, options);
     if (promise !== undefined) return await promise;
   }
-
   options = getOptions(options);
-
+  if (BufferIsBuffer(prefix)) {
+    options = { ...options, encoding: 'buffer' };
+  }
   prefix = getValidatedPath(prefix, 'prefix');
   warnOnNonPortableTemplate(prefix);
 
@@ -2039,7 +2040,9 @@ async function mkdtemp(prefix, options) {
 
 async function mkdtempDisposable(prefix, options) {
   options = getOptions(options);
-
+  if (BufferIsBuffer(prefix)) {
+    options = { ...options, encoding: 'buffer' };
+  }
   prefix = getValidatedPath(prefix, 'prefix');
   warnOnNonPortableTemplate(prefix);
 
diff --git a/test/parallel/test-fs-mkdtemp-buffer.js b/test/parallel/test-fs-mkdtemp-buffer.js
new file mode 100644
index 00000000000000..4403db03570a9a
--- /dev/null
+++ b/test/parallel/test-fs-mkdtemp-buffer.js
@@ -0,0 +1,26 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const fs = require('fs');
+const path = require('path');
+
+const tmpdir = require('../common/tmpdir');
+tmpdir.refresh();
+
+const prefixString = path.join(tmpdir.path, 'buffer-');
+const prefixBuffer = Buffer.from(prefixString);
+
+// 1. Test Sync API
+const resultSync = fs.mkdtempSync(prefixBuffer);
+assert.strictEqual(Buffer.isBuffer(resultSync), true);
+
+// 2. Test Callback API
+fs.mkdtemp(prefixBuffer, common.mustSucceed((resultCb) => {
+  assert.strictEqual(Buffer.isBuffer(resultCb), true);
+}));
+
+// 3. Test Promises API
+fs.promises.mkdtemp(prefixBuffer)
+  .then(common.mustCall((resultPromise) => {
+    assert.strictEqual(Buffer.isBuffer(resultPromise), true);
+  }));
diff --git a/test/parallel/test-fs-mkdtemp.js b/test/parallel/test-fs-mkdtemp.js
index e93809d5b44546..a7d678d21ee02a 100644
--- a/test/parallel/test-fs-mkdtemp.js
+++ b/test/parallel/test-fs-mkdtemp.js
@@ -64,22 +64,13 @@ function handler(err, folder) {
 {
   const tmpFolder = fs.mkdtempSync(Buffer.from(tmpdir.resolve('foo.')));
 
-  assert.strictEqual(path.basename(tmpFolder).length, 'foo.XXXXXX'.length);
+  assert.strictEqual(path.basename(tmpFolder.toString()).length, 'foo.XXXXXX'.length);
   assert(fs.existsSync(tmpFolder));
 
   const utf8 = fs.mkdtempSync(Buffer.from(tmpdir.resolve('\u0222abc.')));
-  assert.strictEqual(Buffer.byteLength(path.basename(utf8)),
+  assert.strictEqual(Buffer.byteLength(path.basename(utf8.toString())),
                      Buffer.byteLength('\u0222abc.XXXXXX'));
   assert(fs.existsSync(utf8));
-
-  fs.mkdtemp(Buffer.from(tmpdir.resolve('bar.')), common.mustCall(handler));
-
-  // Same test as above, but making sure that passing an options object doesn't
-  // affect the way the callback function is handled.
-  fs.mkdtemp(Buffer.from(tmpdir.resolve('bar.')), {}, common.mustCall(handler));
-
-  // Warning fires only once
-  fs.mkdtemp(Buffer.from(tmpdir.resolve('bar.X')), common.mustCall(handler));
 }
 
 // Test with Uint8Array