diff --git a/lib/fs.js b/lib/fs.js
index 6f1f2987208..31ddb1f52b7 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -19,6 +19,12 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+// Maintainers, keep in mind that octal literals are not allowed
+// in strict mode. Use the decimal value and add a comment with
+// the octal value. Example:
+//
+//   var mode = 438; /* mode=0666 */
+
 var util = require('util');
 
 var binding = process.binding('fs');
@@ -110,7 +116,7 @@ fs.readFile = function(path, encoding_) {
 };
 
 fs.readFileSync = function(path, encoding) {
-  var fd = fs.openSync(path, constants.O_RDONLY, 0666);
+  var fd = fs.openSync(path, constants.O_RDONLY, 438 /*=0666*/);
   var buffer = new Buffer(4048);
   var buffers = [];
   var nread = 0;
@@ -212,13 +218,13 @@ fs.open = function(path, flags, mode, callback) {
     callback = noop;
   }
 
-  mode = modeNum(mode, '0666');
+  mode = modeNum(mode, 438 /*=0666*/);
 
   binding.open(path, stringToFlags(flags), mode, callback);
 };
 
 fs.openSync = function(path, flags, mode) {
-  mode = modeNum(mode, '0666');
+  mode = modeNum(mode, 438 /*=0666*/);
   return binding.open(path, stringToFlags(flags), mode);
 };
 
@@ -565,7 +571,7 @@ fs.writeFile = function(path, data, encoding_, callback) {
   var encoding = (typeof(encoding_) == 'string' ? encoding_ : 'utf8');
   var callback_ = arguments[arguments.length - 1];
   callback = (typeof(callback_) == 'function' ? callback_ : null);
-  fs.open(path, 'w', 0666, function(openErr, fd) {
+  fs.open(path, 'w', 438 /*=0666*/, function(openErr, fd) {
     if (openErr) {
       if (callback) callback(openErr);
     } else {
@@ -986,7 +992,7 @@ var ReadStream = fs.ReadStream = function(path, options) {
   this.paused = false;
 
   this.flags = 'r';
-  this.mode = parseInt('0666', 8);
+  this.mode = 438; /*=0666*/
   this.bufferSize = 64 * 1024;
 
   options = options || {};
@@ -1175,7 +1181,7 @@ var WriteStream = fs.WriteStream = function(path, options) {
 
   this.flags = 'w';
   this.encoding = 'binary';
-  this.mode = parseInt('0666', 8);
+  this.mode = 438; /*=0666*/
   this.bytesWritten = 0;
 
   options = options || {};