diff --git a/runtime/bin/file.cc b/runtime/bin/file.cc
index 15088caab93c..59f8300a266f 100644
--- a/runtime/bin/file.cc
+++ b/runtime/bin/file.cc
@@ -59,13 +59,21 @@ bool File::WriteFully(const void* buffer, int64_t num_bytes) {
 File::FileOpenMode File::DartModeToFileMode(DartFileOpenMode mode) {
   ASSERT(mode == File::kDartRead ||
          mode == File::kDartWrite ||
-         mode == File::kDartAppend);
+         mode == File::kDartAppend ||
+         mode == File::kDartWriteOnly ||
+         mode == File::kDartWriteOnlyAppend);
   if (mode == File::kDartWrite) {
     return File::kWriteTruncate;
   }
   if (mode == File::kDartAppend) {
     return File::kWrite;
   }
+  if (mode == File::kDartWriteOnly) {
+    return File::kWriteOnlyTruncate;
+  }
+  if (mode == File::kDartWriteOnlyAppend) {
+    return File::kWriteOnly;
+  }
   return File::kRead;
 }
 
diff --git a/runtime/bin/file.h b/runtime/bin/file.h
index 7a8107fd91f4..633c006175fa 100644
--- a/runtime/bin/file.h
+++ b/runtime/bin/file.h
@@ -26,15 +26,20 @@ class File {
     kRead = 0,
     kWrite = 1,
     kTruncate = 1 << 2,
-    kWriteTruncate = kWrite | kTruncate
+    kWriteOnly = 1 << 3,
+    kWriteTruncate = kWrite | kTruncate,
+    kWriteOnlyTruncate = kWriteOnly | kTruncate
   };
 
   // These values have to be kept in sync with the mode values of
-  // FileMode.READ, FileMode.WRITE and FileMode.APPEND in file.dart.
+  // FileMode.READ, FileMode.WRITE, FileMode.APPEND,
+  // FileMode.WRITE_ONLY and FileMode.WRITE_ONLY_APPEND in file.dart.
   enum DartFileOpenMode {
     kDartRead = 0,
     kDartWrite = 1,
-    kDartAppend = 2
+    kDartAppend = 2,
+    kDartWriteOnly = 3,
+    kDartWriteOnlyAppend = 4
   };
 
   enum Type {
diff --git a/runtime/bin/file_android.cc b/runtime/bin/file_android.cc
index 015fc0ad53c0..35b6388b6e5c 100644
--- a/runtime/bin/file_android.cc
+++ b/runtime/bin/file_android.cc
@@ -158,8 +158,13 @@ File* File::Open(const char* name, FileOpenMode mode) {
   }
   int flags = O_RDONLY;
   if ((mode & kWrite) != 0) {
+    ASSERT((mode & kWriteOnly) == 0);
     flags = (O_RDWR | O_CREAT);
   }
+  if ((mode & kWriteOnly) != 0) {
+    ASSERT((mode & kWrite) == 0);
+    flags = (O_WRONLY | O_CREAT);
+  }
   if ((mode & kTruncate) != 0) {
     flags = flags | O_TRUNC;
   }
@@ -168,7 +173,8 @@ File* File::Open(const char* name, FileOpenMode mode) {
   if (fd < 0) {
     return NULL;
   }
-  if (((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) {
+  if ((((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) ||
+      (((mode & kWriteOnly) != 0) && ((mode & kTruncate) == 0))) {
     int64_t position = lseek64(fd, 0, SEEK_END);
     if (position < 0) {
       return NULL;
diff --git a/runtime/bin/file_linux.cc b/runtime/bin/file_linux.cc
index 0a437f14874f..ff801adf8fe7 100644
--- a/runtime/bin/file_linux.cc
+++ b/runtime/bin/file_linux.cc
@@ -157,8 +157,13 @@ File* File::Open(const char* name, FileOpenMode mode) {
   }
   int flags = O_RDONLY;
   if ((mode & kWrite) != 0) {
+    ASSERT((mode & kWriteOnly) == 0);
     flags = (O_RDWR | O_CREAT);
   }
+  if ((mode & kWriteOnly) != 0) {
+    ASSERT((mode & kWrite) == 0);
+    flags = (O_WRONLY | O_CREAT);
+  }
   if ((mode & kTruncate) != 0) {
     flags = flags | O_TRUNC;
   }
@@ -167,7 +172,8 @@ File* File::Open(const char* name, FileOpenMode mode) {
   if (fd < 0) {
     return NULL;
   }
-  if (((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) {
+  if ((((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) ||
+      (((mode & kWriteOnly) != 0) && ((mode & kTruncate) == 0))) {
     int64_t position = NO_RETRY_EXPECTED(lseek64(fd, 0, SEEK_END));
     if (position < 0) {
       return NULL;
diff --git a/runtime/bin/file_macos.cc b/runtime/bin/file_macos.cc
index 9fc33c5b4936..ddc19cc02979 100644
--- a/runtime/bin/file_macos.cc
+++ b/runtime/bin/file_macos.cc
@@ -159,8 +159,13 @@ File* File::Open(const char* name, FileOpenMode mode) {
   }
   int flags = O_RDONLY;
   if ((mode & kWrite) != 0) {
+    ASSERT((mode & kWriteOnly) == 0);
     flags = (O_RDWR | O_CREAT);
   }
+  if ((mode & kWriteOnly) != 0) {
+    ASSERT((mode & kWrite) == 0);
+    flags = (O_WRONLY | O_CREAT);
+  }
   if ((mode & kTruncate) != 0) {
     flags = flags | O_TRUNC;
   }
@@ -169,7 +174,8 @@ File* File::Open(const char* name, FileOpenMode mode) {
     return NULL;
   }
   FDUtils::SetCloseOnExec(fd);
-  if (((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) {
+  if ((((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) ||
+      (((mode & kWriteOnly) != 0) && ((mode & kTruncate) == 0))) {
     int64_t position = lseek(fd, 0, SEEK_END);
     if (position < 0) {
       return NULL;
diff --git a/runtime/bin/file_win.cc b/runtime/bin/file_win.cc
index 67b97f51af16..0fde43360385 100644
--- a/runtime/bin/file_win.cc
+++ b/runtime/bin/file_win.cc
@@ -157,8 +157,13 @@ int64_t File::Length() {
 File* File::Open(const char* name, FileOpenMode mode) {
   int flags = O_RDONLY | O_BINARY | O_NOINHERIT;
   if ((mode & kWrite) != 0) {
+    ASSERT((mode & kWriteOnly) == 0);
     flags = (O_RDWR | O_CREAT | O_BINARY | O_NOINHERIT);
   }
+  if ((mode & kWriteOnly) != 0) {
+    ASSERT((mode & kWrite) == 0);
+    flags = (O_WRONLY | O_CREAT | O_BINARY | O_NOINHERIT);
+  }
   if ((mode & kTruncate) != 0) {
     flags = flags | O_TRUNC;
   }
@@ -168,7 +173,8 @@ File* File::Open(const char* name, FileOpenMode mode) {
   if (fd < 0) {
     return NULL;
   }
-  if (((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) {
+  if ((((mode & kWrite) != 0) && ((mode & kTruncate) == 0)) ||
+      (((mode & kWriteOnly) != 0) && ((mode & kTruncate) == 0))) {
     int64_t position = _lseeki64(fd, 0, SEEK_END);
     if (position < 0) {
       return NULL;
diff --git a/sdk/lib/io/file.dart b/sdk/lib/io/file.dart
index 879915825fa5..691d7837445f 100644
--- a/sdk/lib/io/file.dart
+++ b/sdk/lib/io/file.dart
@@ -10,13 +10,20 @@ part of dart.io;
 class FileMode {
   /// The mode for opening a file only for reading.
   static const READ = const FileMode._internal(0);
-  /// The mode for opening a file for reading and writing. The file is
+  /// Mode for opening a file for reading and writing. The file is
   /// overwritten if it already exists. The file is created if it does not
   /// already exist.
   static const WRITE = const FileMode._internal(1);
-  /// The mode for opening a file for reading and writing to the
+  /// Mode for opening a file for reading and writing to the
   /// end of it. The file is created if it does not already exist.
   static const APPEND = const FileMode._internal(2);
+  /// Mode for opening a file for writing *only*. The file is
+  /// overwritten if it already exists. The file is created if it does not
+  /// already exist.
+  static const WRITE_ONLY = const FileMode._internal(3);
+  /// Mode for opening a file for writing *only* to the
+  /// end of it. The file is created if it does not already exist.
+  static const WRITE_ONLY_APPEND = const FileMode._internal(4);
   final int _mode;
 
   const FileMode._internal(this._mode);
@@ -31,6 +38,13 @@ const WRITE = FileMode.WRITE;
 /// The mode for opening a file for reading and writing to the
 /// end of it. The file is created if it does not already exist.
 const APPEND = FileMode.APPEND;
+/// Mode for opening a file for writing *only*. The file is
+/// overwritten if it already exists. The file is created if it does not
+/// already exist.
+const WRITE_ONLY = FileMode.WRITE_ONLY;
+/// Mode for opening a file for writing *only* to the
+/// end of it. The file is created if it does not already exist.
+const WRITE_ONLY_APPEND = FileMode.WRITE_ONLY_APPEND;
 
 
 /// Type of lock when requesting a lock on a file.
diff --git a/sdk/lib/io/file_impl.dart b/sdk/lib/io/file_impl.dart
index a98d94826716..8ed6c58b89b8 100644
--- a/sdk/lib/io/file_impl.dart
+++ b/sdk/lib/io/file_impl.dart
@@ -344,8 +344,11 @@ class _File extends FileSystemEntity implements File {
   Future<RandomAccessFile> open({FileMode mode: FileMode.READ}) {
     if (mode != FileMode.READ &&
         mode != FileMode.WRITE &&
-        mode != FileMode.APPEND) {
-      return new Future.error(new ArgumentError());
+        mode != FileMode.APPEND &&
+        mode != FileMode.WRITE_ONLY &&
+        mode != FileMode.WRITE_ONLY_APPEND) {
+      return new Future.error(
+          new ArgumentError('Invalid file mode for this operation'));
     }
     return _IOService._dispatch(_FILE_OPEN, [path, mode._mode])
         .then((response) {
@@ -401,10 +404,10 @@ class _File extends FileSystemEntity implements File {
   RandomAccessFile openSync({FileMode mode: FileMode.READ}) {
     if (mode != FileMode.READ &&
         mode != FileMode.WRITE &&
-        mode != FileMode.APPEND) {
-      throw new FileSystemException("Unknown file mode. Use FileMode.READ, "
-                              "FileMode.WRITE or FileMode.APPEND.",
-                              path);
+        mode != FileMode.APPEND &&
+        mode != FileMode.WRITE_ONLY &&
+        mode != FileMode.WRITE_ONLY_APPEND) {
+      throw new ArgumentError('Invalid file mode for this operation');
     }
     var id = _open(path, mode._mode);
     throwIfError(id, "Cannot open file", path);
@@ -428,9 +431,10 @@ class _File extends FileSystemEntity implements File {
   IOSink openWrite({FileMode mode: FileMode.WRITE,
                     Encoding encoding: UTF8}) {
     if (mode != FileMode.WRITE &&
-        mode != FileMode.APPEND) {
-      throw new ArgumentError(
-          "Wrong FileMode. Use FileMode.WRITE or FileMode.APPEND");
+        mode != FileMode.APPEND &&
+        mode != FileMode.WRITE_ONLY &&
+        mode != FileMode.WRITE_ONLY_APPEND) {
+      throw new ArgumentError('Invalid file mode for this operation');
     }
     var consumer = new _FileStreamConsumer(this, mode);
     return new IOSink(consumer, encoding: encoding);
diff --git a/tests/standalone/io/file_write_only_test.dart b/tests/standalone/io/file_write_only_test.dart
new file mode 100644
index 000000000000..c06be4741ef8
--- /dev/null
+++ b/tests/standalone/io/file_write_only_test.dart
@@ -0,0 +1,84 @@
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// Dart test program for testing file I/O.
+
+import 'dart:async';
+import 'dart:io';
+
+import "package:async_helper/async_helper.dart";
+import "package:expect/expect.dart";
+
+Future withTempDir(String prefix, void test(Directory dir)) async {
+  var tempDir = Directory.systemTemp.createTempSync(prefix);
+  try {
+    await test(tempDir);
+  } finally {
+    tempDir.deleteSync(recursive: true);
+  }
+}
+
+void withTempDirSync(String prefix, void test(Directory dir)) async {
+  var tempDir = Directory.systemTemp.createTempSync(prefix);
+  try {
+    test(tempDir);
+  } finally {
+    tempDir.deleteSync(recursive: true);
+  }
+}
+
+Futire expectThrowsAsync(Future future, String message) {
+  return future.then((r) => Expect.fail(message))
+               .catchError((e) {});
+}
+
+
+Future write(Directory dir) async {
+  var f = new File('x');
+  var raf = await f.open(mode: WRITE_ONLY);
+  await raf.writeString('Hello');
+  await raf.setPosition(0);
+  await raf.writeString('Hello');
+  await raf.setPosition(0);
+  await expectThrowsAsync(
+      raf.readByte(), 'Read from write only file succeeded');
+  await raf.close();
+  raf = await f.open(mode: WRITE_ONLY_APPEND);
+  await raf.writeString('Hello');
+  await expectThrowsAsync(
+      raf.readByte(), 'Read from write only file succeeded');
+  await raf.setPosition(0);
+  await raf.writeString('Hello');
+  await raf.close();
+  Expect.equals(f.lengthSync(), 10);
+}
+
+Future writeSync(Directory dir) {
+  var f = new File('x');
+  var raf = f.openSync(mode: WRITE_ONLY);
+  raf.writeStringSync('Hello');
+  raf.setPositionSync(0);
+  raf.writeStringSync('Hello');
+  raf.setPositionSync(0);
+  Expect.throws(() => raf.readByteSync());
+}
+
+Future openWrite(Directory dir) async {
+  var f = new File('x');
+  var sink = f.openWrite(mode: WRITE_ONLY);
+  sink.write('Hello');
+  await sink.close();
+  sink = await f.openWrite(mode: WRITE_ONLY_APPEND);
+  sink.write('Hello');
+  await sink.close();
+  Expect.equals(f.lengthSync(), 10);
+}
+
+main() async {
+  asyncStart();
+  await withTempDir('file_write_only_test', write);
+  withTempDirSync('file_write_only_test', writeSync);
+  await withTempDir('file_write_only_test', openWrite);
+  asyncEnd();
+}