diff --git a/BUILD.gn b/BUILD.gn
index 7c29e42583..259c5bdc44 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -72,6 +72,7 @@ ts_sources = [
   "js/console.ts",
   "js/copy_file.ts",
   "js/deno.ts",
+  "js/dir.ts",
   "js/dispatch.ts",
   "js/dom_types.ts",
   "js/errors.ts",
@@ -107,7 +108,6 @@ ts_sources = [
   "js/util.ts",
   "js/v8_source_maps.ts",
   "js/write_file.ts",
-
   "tsconfig.json",
 
   # Listing package.json and yarn.lock as sources ensures the bundle is rebuilt
diff --git a/js/deno.ts b/js/deno.ts
index 2125445411..565d4a7e6c 100644
--- a/js/deno.ts
+++ b/js/deno.ts
@@ -2,6 +2,7 @@
 // Public deno module.
 /// <amd-module name="deno"/>
 export { env, exit } from "./os";
+export { chdir, cwd } from "./dir";
 export { File, open, stdin, stdout, stderr, read, write, close } from "./files";
 export {
   copy,
diff --git a/js/dir.ts b/js/dir.ts
new file mode 100644
index 0000000000..4bd3e6bd7c
--- /dev/null
+++ b/js/dir.ts
@@ -0,0 +1,37 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import * as msg from "gen/msg_generated";
+import { assert } from "./util";
+import { flatbuffers } from "flatbuffers";
+import { sendSync } from "./dispatch";
+
+/**
+ * cwd() Return a string representing the current working directory.
+ * If the current directory can be reached via multiple paths
+ * (due to symbolic links), cwd() may return
+ * any one of them.
+ * throws NotFound exception if directory not available
+ */
+export function cwd(): string {
+  const builder = new flatbuffers.Builder(0);
+  msg.Cwd.startCwd(builder);
+  const inner = msg.Cwd.endCwd(builder);
+  const baseRes = sendSync(builder, msg.Any.Cwd, inner);
+  assert(baseRes != null);
+  assert(msg.Any.CwdRes === baseRes!.innerType());
+  const res = new msg.CwdRes();
+  assert(baseRes!.inner(res) != null);
+  return res.cwd()!;
+}
+
+/**
+ * chdir() Change the current working directory to path.
+ * throws NotFound exception if directory not available
+ */
+export function chdir(directory: string): void {
+  const builder = new flatbuffers.Builder();
+  const directory_ = builder.createString(directory);
+  msg.Chdir.startChdir(builder);
+  msg.Chdir.addDirectory(builder, directory_);
+  const inner = msg.Chdir.endChdir(builder);
+  sendSync(builder, msg.Any.Chdir, inner);
+}
diff --git a/js/dir_test.ts b/js/dir_test.ts
new file mode 100644
index 0000000000..ff55a0e696
--- /dev/null
+++ b/js/dir_test.ts
@@ -0,0 +1,54 @@
+import { test, testPerm, assert, assertEqual } from "./test_util.ts";
+import * as deno from "deno";
+
+test(function dirCwdNotNull() {
+  assert(deno.cwd() != null);
+});
+
+testPerm({ write: true }, function dirCwdChdirSuccess() {
+  const initialdir = deno.cwd();
+  const path = deno.makeTempDirSync();
+  deno.chdir(path);
+  const current = deno.cwd();
+  if (deno.platform.os === "mac") {
+    assertEqual(current, "/private" + path);
+  } else {
+    assertEqual(current, path);
+  }
+  deno.chdir(initialdir);
+});
+
+testPerm({ write: true }, function dirCwdError() {
+  // excluding windows since it throws resource busy, while removeSync
+  if (["linux", "mac"].includes(deno.platform.os)) {
+    const initialdir = deno.cwd();
+    const path = deno.makeTempDirSync();
+    deno.chdir(path);
+    deno.removeSync(path);
+    try {
+      deno.cwd();
+      throw Error("current directory removed, should throw error");
+    } catch (err) {
+      if (err instanceof deno.DenoError) {
+        console.log(err.name === "NotFound");
+      } else {
+        throw Error("raised different exception");
+      }
+    }
+    deno.chdir(initialdir);
+  }
+});
+
+testPerm({ write: true }, function dirChdirError() {
+  const path = deno.makeTempDirSync() + "test";
+  try {
+    deno.chdir(path);
+    throw Error("directory not available, should throw error");
+  } catch (err) {
+    if (err instanceof deno.DenoError) {
+      console.log(err.name === "NotFound");
+    } else {
+      throw Error("raised different exception");
+    }
+  }
+});
diff --git a/js/unit_tests.ts b/js/unit_tests.ts
index 24fdac8234..e09d0aba02 100644
--- a/js/unit_tests.ts
+++ b/js/unit_tests.ts
@@ -11,6 +11,7 @@ import "./read_dir_test.ts";
 import "./write_file_test.ts";
 import "./copy_file_test.ts";
 import "./mkdir_test.ts";
+import "./dir_test";
 import "./make_temp_dir_test.ts";
 import "./stat_test.ts";
 import "./rename_test.ts";
diff --git a/src/msg.fbs b/src/msg.fbs
index 43fde4d688..5b60213ade 100644
--- a/src/msg.fbs
+++ b/src/msg.fbs
@@ -41,6 +41,9 @@ union Any {
   Accept,
   Dial,
   NewConn,
+  Chdir,
+  Cwd,
+  CwdRes,
   Metrics,
   MetricsRes,
 }
@@ -93,6 +96,12 @@ enum ErrorKind: byte {
   HttpOther,
 }
 
+table Cwd {}
+
+table CwdRes {
+  cwd: string;
+}
+
 table Base {
   cmd_id: uint32;
   sync: bool = true; // TODO(ry) Change default to false.
@@ -135,6 +144,10 @@ table CodeCache {
   output_code: string;
 }
 
+table Chdir {
+  directory: string;
+}
+
 table SetTimeout {
   timeout: double;
 }
diff --git a/src/ops.rs b/src/ops.rs
index a58532bafc..261ed67f5d 100644
--- a/src/ops.rs
+++ b/src/ops.rs
@@ -101,6 +101,8 @@ pub fn dispatch(
       msg::Any::Listen => op_listen,
       msg::Any::Accept => op_accept,
       msg::Any::Dial => op_dial,
+      msg::Any::Chdir => op_chdir,
+      msg::Any::Cwd => op_cwd,
       msg::Any::Metrics => op_metrics,
       _ => panic!(format!(
         "Unhandled message {}",
@@ -110,8 +112,7 @@ pub fn dispatch(
     op_creator(isolate.state.clone(), &base, data)
   };
 
-  let boxed_op = Box::new(
-    op.or_else(move |err: DenoError| -> DenoResult<Buf> {
+  let boxed_op = Box::new(op.or_else(move |err: DenoError| -> DenoResult<Buf> {
       debug!("op err {}", err);
       // No matter whether we got an Err or Ok, we want a serialized message to
       // send back. So transform the DenoError into a deno_buf.
@@ -143,8 +144,7 @@ pub fn dispatch(
         )
       };
       Ok(buf)
-    }),
-  );
+    }));
 
   debug!(
     "msg_from_js {} sync {}",
@@ -283,6 +283,20 @@ fn op_code_cache(
   }()))
 }
 
+fn op_chdir(
+  _state: Arc<IsolateState>,
+  base: &msg::Base,
+  data: &'static mut [u8],
+) -> Box<Op> {
+  assert_eq!(data.len(), 0);
+  let inner = base.inner_as_chdir().unwrap();
+  let directory = inner.directory().unwrap();
+  Box::new(futures::future::result(|| -> OpResult {
+    let _result = std::env::set_current_dir(&directory)?;
+    Ok(empty_buf())
+  }()))
+}
+
 fn op_set_timeout(
   isolate: &mut Isolate,
   base: &msg::Base,
@@ -811,6 +825,37 @@ fn get_mode(_perm: fs::Permissions) -> u32 {
   0
 }
 
+fn op_cwd(
+  _state: Arc<IsolateState>,
+  base: &msg::Base,
+  data: &'static mut [u8],
+) -> Box<Op> {
+  assert_eq!(data.len(), 0);
+  let cmd_id = base.cmd_id();
+  Box::new(futures::future::result(|| -> OpResult {
+    let path = std::env::current_dir()?;
+    let builder = &mut FlatBufferBuilder::new();
+    let cwd =
+      builder.create_string(&path.into_os_string().into_string().unwrap());
+    let inner = msg::CwdRes::create(
+      builder,
+      &msg::CwdResArgs {
+        cwd: Some(cwd),
+        ..Default::default()
+      },
+    );
+    Ok(serialize_response(
+      cmd_id,
+      builder,
+      msg::BaseArgs {
+        inner: Some(inner.as_union_value()),
+        inner_type: msg::Any::CwdRes,
+        ..Default::default()
+      },
+    ))
+  }()))
+}
+
 fn op_stat(
   _config: Arc<IsolateState>,
   base: &msg::Base,