diff --git a/js/mkdir_test.ts b/js/mkdir_test.ts
index ed275bd363..4f82401dcc 100644
--- a/js/mkdir_test.ts
+++ b/js/mkdir_test.ts
@@ -9,6 +9,15 @@ testPerm({ write: true }, function mkdirSyncSuccess() {
   assert(pathInfo.isDirectory());
 });
 
+testPerm({ write: true }, function mkdirSyncMode() {
+  const path = deno.makeTempDirSync() + "/dir/subdir";
+  deno.mkdirSync(path, 0o755); // no perm for x
+  const pathInfo = deno.statSync(path);
+  if (pathInfo.mode !== null) { // Skip windows
+    assertEqual(pathInfo.mode & 0o777, 0o755);
+  }
+});
+
 testPerm({ write: false }, function mkdirSyncPerm() {
   let err;
   try {
diff --git a/js/stat.ts b/js/stat.ts
index 3193794a5d..434841ec2e 100644
--- a/js/stat.ts
+++ b/js/stat.ts
@@ -51,7 +51,8 @@ export class FileInfo {
     this.modified = modified ? modified : null;
     this.accessed = accessed ? accessed : null;
     this.created = created ? created : null;
-    this.mode = mode >= 0 ? mode : null; // null if invalid mode (Windows)
+    // null if invalid mode (Windows)
+    this.mode = mode >= 0 ? mode & 0o7777 : null;
   }
 
   /**
diff --git a/src/deno_dir.rs b/src/deno_dir.rs
index a8379b9005..53fbf5ba8b 100644
--- a/src/deno_dir.rs
+++ b/src/deno_dir.rs
@@ -55,8 +55,8 @@ impl DenoDir {
       deps,
       reload,
     };
-    deno_fs::mkdir(deno_dir.gen.as_ref())?;
-    deno_fs::mkdir(deno_dir.deps.as_ref())?;
+    deno_fs::mkdir(deno_dir.gen.as_ref(), 0o755)?;
+    deno_fs::mkdir(deno_dir.deps.as_ref(), 0o755)?;
 
     debug!("root {}", deno_dir.root.display());
     debug!("gen {}", deno_dir.gen.display());
diff --git a/src/fs.rs b/src/fs.rs
index e04675f66d..33323b87bf 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -1,5 +1,5 @@
 use std;
-use std::fs::{create_dir, File, OpenOptions};
+use std::fs::{create_dir, DirBuilder, File, OpenOptions};
 use std::io::ErrorKind;
 use std::io::Write;
 use std::path::{Path, PathBuf};
@@ -7,6 +7,8 @@ use std::path::{Path, PathBuf};
 use rand;
 use rand::Rng;
 
+#[cfg(any(unix))]
+use std::os::unix::fs::DirBuilderExt;
 #[cfg(any(unix))]
 use std::os::unix::fs::PermissionsExt;
 
@@ -64,18 +66,28 @@ pub fn make_temp_dir(
   }
 }
 
-pub fn mkdir(path: &Path) -> std::io::Result<()> {
+pub fn mkdir(path: &Path, perm: u32) -> std::io::Result<()> {
   debug!("mkdir -p {}", path.display());
-  assert!(path.has_root(), "non-has_root not yet implemented");
-  std::fs::create_dir_all(path).or_else(|err| {
-    if err.kind() == std::io::ErrorKind::AlreadyExists {
-      Ok(())
-    } else {
-      Err(err)
-    }
+  let mut builder = DirBuilder::new();
+  builder.recursive(true);
+  set_dir_permission(&mut builder, perm);
+  builder.create(path).or_else(|err| match err.kind() {
+    std::io::ErrorKind::AlreadyExists => Ok(()),
+    _ => Err(err),
   })
 }
 
+#[cfg(any(unix))]
+fn set_dir_permission(builder: &mut DirBuilder, perm: u32) {
+  debug!("set dir perm to {}", perm);
+  builder.mode(perm);
+}
+
+#[cfg(not(any(unix)))]
+fn set_dir_permission(_builder: &mut DirBuilder, _perm: u32) {
+  // NOOP on windows
+}
+
 pub fn normalize_path(path: &Path) -> String {
   let s = String::from(path.to_str().unwrap());
   if cfg!(windows) {
diff --git a/src/handlers.rs b/src/handlers.rs
index 641bfd83c1..0917fd22ab 100644
--- a/src/handlers.rs
+++ b/src/handlers.rs
@@ -451,7 +451,7 @@ fn handle_make_temp_dir(d: *const DenoC, base: &msg::Base) -> Box<Op> {
 
 fn handle_mkdir(d: *const DenoC, base: &msg::Base) -> Box<Op> {
   let msg = base.msg_as_mkdir().unwrap();
-  // TODO let mode = msg.mode();
+  let mode = msg.mode();
   let path = msg.path().unwrap();
   let deno = from_c(d);
   if !deno.flags.allow_write {
@@ -460,8 +460,7 @@ fn handle_mkdir(d: *const DenoC, base: &msg::Base) -> Box<Op> {
   // TODO Use tokio_threadpool.
   Box::new(futures::future::result(|| -> OpResult {
     debug!("handle_mkdir {}", path);
-    // TODO(ry) Use mode.
-    deno_fs::mkdir(Path::new(path))?;
+    deno_fs::mkdir(Path::new(path), mode)?;
     Ok(None)
   }()))
 }