diff --git a/demo/fsa/main.ts b/demo/fsa/main.ts
index 4808e3428..1a016b76e 100644
--- a/demo/fsa/main.ts
+++ b/demo/fsa/main.ts
@@ -61,11 +61,16 @@ const demo = async (dir: fsa.IFileSystemDirectoryHandle) => {
   console.log('mkdirSync() - can create a nested directory');
   fs.mkdirSync('/public/site/assets/img', {recursive: true});
   strictEqual(fs.statSync('/public/site/assets/img').isDirectory(), true);
+
+  console.log('mkdtempSync() - can create a temporary directory');
+  await fs.promises.mkdir('/tmp');
+  const tmpDirName = fs.mkdtempSync('/tmp/temporary-');
+  strictEqual(fs.statSync(tmpDirName).isDirectory(), true);
 };
 
 const main = async () => {
   const button = document.createElement("button");
-  button.textContent = "Select folder";
+  button.textContent = "Select an empty folder";
   document.body.appendChild(button);
   button.onclick = async () => {
     const dir = await (window as any).showDirectoryPicker({id: 'demo', mode: 'readwrite'});
diff --git a/src/fsa-to-node/FsaNodeFs.ts b/src/fsa-to-node/FsaNodeFs.ts
index 438653e31..d2bf8f601 100644
--- a/src/fsa-to-node/FsaNodeFs.ts
+++ b/src/fsa-to-node/FsaNodeFs.ts
@@ -15,6 +15,7 @@ import {
   getOptions,
   getStatOptions,
   getAppendFileOpts,
+  getDefaultOpts,
 } from '../node/options';
 import {
   bufToUint8,
@@ -875,10 +876,16 @@ export class FsaNodeFs extends FsaNodeCore implements FsCallbackApi, FsSynchrono
     return this.getSyncAdapter().call('mkdir', [filename, options]);
   };
 
+  public readonly mkdtempSync: FsSynchronousApi['mkdtempSync'] = (prefix: string, options?: opts.IOptions): misc.TDataOut => {
+    const {encoding} = getDefaultOpts(options);
+    if (!prefix || typeof prefix !== 'string') throw new TypeError('filename prefix is required');
+    nullCheck(prefix);
+    const result = this.getSyncAdapter().call('mkdtemp', [prefix, options]);
+    return strToEncoding(result, encoding);
+  };
+
   public readonly ftruncateSync: FsSynchronousApi['ftruncateSync'] = notSupported;
   public readonly linkSync: FsSynchronousApi['linkSync'] = notSupported;
-  public readonly mkdirpSync: FsSynchronousApi['mkdirpSync'] = notSupported;
-  public readonly mkdtempSync: FsSynchronousApi['mkdtempSync'] = notSupported;
   public readonly openSync: FsSynchronousApi['openSync'] = notSupported;
   public readonly readdirSync: FsSynchronousApi['readdirSync'] = notSupported;
   public readonly readlinkSync: FsSynchronousApi['readlinkSync'] = notSupported;
diff --git a/src/fsa-to-node/types.ts b/src/fsa-to-node/types.ts
index de228468b..24db7d05e 100644
--- a/src/fsa-to-node/types.ts
+++ b/src/fsa-to-node/types.ts
@@ -17,6 +17,7 @@ export interface FsaNodeSyncAdapterApi {
   rmdir(req: [filename: string, opts?: opts.IRmdirOptions]): void;
   rm(req: [filename: string, opts?: opts.IRmOptions]): void;
   mkdir(req: [filename: string, opts?: misc.TMode | opts.IMkdirOptions]): string | undefined;
+  mkdtemp(req: [filename: string, opts?: misc.TMode | opts.IOptions]): string;
 }
 
 export interface FsaNodeSyncAdapter {
diff --git a/src/fsa-to-node/worker/FsaNodeSyncWorker.ts b/src/fsa-to-node/worker/FsaNodeSyncWorker.ts
index 803e0a9eb..70f2f8f39 100644
--- a/src/fsa-to-node/worker/FsaNodeSyncWorker.ts
+++ b/src/fsa-to-node/worker/FsaNodeSyncWorker.ts
@@ -150,5 +150,8 @@ export class FsaNodeSyncWorker {
     mkdir: async ([filename, options]): Promise<string | undefined> => {
       return await this.fs.promises.mkdir(filename, options);
     },
+    mkdtemp: async ([filename]): Promise<string> => {
+      return await this.fs.promises.mkdtemp(filename, {encoding: 'utf8'}) as string;
+    },
   };
 }
diff --git a/src/node/types/FsSynchronousApi.ts b/src/node/types/FsSynchronousApi.ts
index 01d4a5d53..3a4fc2d28 100644
--- a/src/node/types/FsSynchronousApi.ts
+++ b/src/node/types/FsSynchronousApi.ts
@@ -58,7 +58,6 @@ export interface FsSynchronousApi {
   mkdirSync(path: misc.PathLike, options: opts.IMkdirOptions & { recursive: true }): string | undefined;
   mkdirSync(path: misc.PathLike, options?: misc.TMode | (opts.IMkdirOptions & { recursive?: false })): void;
   mkdirSync(path: misc.PathLike, options?: misc.TMode | opts.IMkdirOptions): string | undefined;
-  mkdirpSync(path: misc.PathLike, mode?: misc.TMode): void;
   mkdtempSync(prefix: string, options?: opts.IOptions): misc.TDataOut;
   rmdirSync(path: misc.PathLike, options?: opts.IRmdirOptions): void;
   rmSync(path: misc.PathLike, options?: opts.IRmOptions): void;