diff --git a/lib/coffee-script.js b/lib/coffee-script.js
index 0d5486ef..a1fe3476 100755
--- a/lib/coffee-script.js
+++ b/lib/coffee-script.js
@@ -1,7 +1,8 @@
 (function() {
-  var Lexer, RESERVED, compile, fs, lexer, parser, path, _ref;
+  var Lexer, RESERVED, compile, fs, lexer, parser, path, vm, _ref;
   fs = require('fs');
   path = require('path');
+  vm = require('vm');
   _ref = require('./lexer'), Lexer = _ref.Lexer, RESERVED = _ref.RESERVED;
   parser = require('./parser').parser;
   if (require.extensions) {
@@ -64,11 +65,30 @@
     }
   };
   exports.eval = function(code, options) {
-    global.__filename = module.filename = process.argv[1] = options.filename;
-    global.__dirname = path.dirname(__filename);
-    global.require = require;
-    global.module = module;
-    return (0, eval)(compile(code, options));
+    var g, js, sandbox;
+    if (options == null) {
+      options = {};
+    }
+    sandbox = options.sandbox;
+    if (!sandbox) {
+      sandbox = {
+        require: require,
+        module: {
+          exports: {}
+        },
+        global: {}
+      };
+      for (g in global) {
+        sandbox[g] = global[g];
+      }
+      sandbox.global.global = sandbox.global;
+      sandbox.global.root = sandbox.global;
+      sandbox.global.GLOBAL = sandbox.global;
+    }
+    sandbox.__filename = options.filename || 'eval';
+    sandbox.__dirname = path.dirname(sandbox.__filename);
+    js = compile("_=(" + (code.trim()) + ")", options);
+    return vm.runInNewContext(js, sandbox, sandbox.__filename);
   };
   lexer = new Lexer;
   parser.lexer = {
diff --git a/lib/repl.js b/lib/repl.js
index 865cf91e..c7bc51c3 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -15,27 +15,44 @@
     return stdout.write((err.stack || err.toString()) + '\n\n');
   };
   backlog = '';
-  run = function(buffer) {
-    var code, val;
-    code = backlog += '\n' + buffer.toString();
-    if (code[code.length - 1] === '\\') {
-      return backlog = backlog.slice(0, backlog.length - 1);
+  run = (function() {
+    var g, sandbox;
+    sandbox = {
+      require: require,
+      module: {
+        exports: {}
+      },
+      global: {}
+    };
+    for (g in global) {
+      sandbox[g] = global[g];
     }
-    backlog = '';
-    try {
-      val = CoffeeScript.eval(code, {
-        bare: true,
-        globals: true,
-        filename: 'repl'
-      });
-      if (val !== void 0) {
-        process.stdout.write(inspect(val, false, 2, enableColours) + '\n');
+    sandbox.global.global = sandbox.global;
+    sandbox.global.root = sandbox.global;
+    sandbox.global.GLOBAL = sandbox.global;
+    return function(buffer) {
+      var code, val;
+      code = backlog += '\n' + buffer.toString();
+      if (code[code.length - 1] === '\\') {
+        return backlog = backlog.slice(0, backlog.length - 1);
       }
-    } catch (err) {
-      error(err);
-    }
-    return repl.prompt();
-  };
+      backlog = '';
+      try {
+        val = CoffeeScript.eval(code, {
+          sandbox: sandbox,
+          bare: true,
+          globals: true,
+          filename: 'repl'
+        });
+        if (val !== void 0) {
+          process.stdout.write(inspect(val, false, 2, enableColours) + '\n');
+        }
+      } catch (err) {
+        error(err);
+      }
+      return repl.prompt();
+    };
+  })();
   ACCESSOR = /\s*([\w\.]+)(?:\.(\w*))$/;
   SIMPLEVAR = /\s*(\w*)$/i;
   autocomplete = function(text) {
diff --git a/src/coffee-script.coffee b/src/coffee-script.coffee
index a2357faf..c63a1cc7 100755
--- a/src/coffee-script.coffee
+++ b/src/coffee-script.coffee
@@ -8,6 +8,7 @@
 
 fs               = require 'fs'
 path             = require 'path'
+vm               = require 'vm'
 {Lexer,RESERVED} = require './lexer'
 {parser}         = require './parser'
 
@@ -77,12 +78,21 @@ exports.run = (code, options) ->
 
 # Compile and evaluate a string of CoffeeScript (in a Node.js-like environment).
 # The CoffeeScript REPL uses this to run the input.
-exports.eval = (code, options) ->
-  global.__filename = module.filename = process.argv[1] = options.filename
-  global.__dirname  = path.dirname __filename
-  global.require    = require
-  global.module     = module
-  (0;eval) compile code, options
+exports.eval = (code, options = {}) ->
+  sandbox = options.sandbox
+  unless sandbox
+    sandbox =
+      require: require
+      module : { exports: {} }
+      global : {}
+    sandbox[g] = global[g] for g of global
+    sandbox.global.global = sandbox.global
+    sandbox.global.root   = sandbox.global
+    sandbox.global.GLOBAL = sandbox.global
+  sandbox.__filename = options.filename || 'eval'
+  sandbox.__dirname  = path.dirname sandbox.__filename
+  js = compile "_=(#{code.trim()})", options
+  vm.runInNewContext js, sandbox, sandbox.__filename
 
 # Instantiate a Lexer for our use here.
 lexer = new Lexer
diff --git a/src/repl.coffee b/src/repl.coffee
index 59b2f4ce..6731fa60 100644
--- a/src/repl.coffee
+++ b/src/repl.coffee
@@ -31,18 +31,32 @@ backlog = ''
 # The main REPL function. **run** is called every time a line of code is entered.
 # Attempt to evaluate the command. If there's an exception, print it out instead
 # of exiting.
-run = (buffer) ->
-  code = backlog += '\n' + buffer.toString()
-  if code[code.length - 1] is '\\'
-    return backlog = backlog[0...backlog.length - 1]
-  backlog = ''
-  try
-    val = CoffeeScript.eval code, bare: on, globals: on, filename: 'repl'
-    unless val is undefined
-      process.stdout.write inspect(val, no, 2, enableColours) + '\n'
-  catch err
-    error err
-  repl.prompt()
+run = do ->
+  sandbox =
+    require: require
+    module : { exports: {} }
+    global : {}
+  sandbox[g] = global[g] for g of global
+  sandbox.global.global = sandbox.global
+  sandbox.global.root   = sandbox.global
+  sandbox.global.GLOBAL = sandbox.global
+  (buffer) ->
+    code = backlog += '\n' + buffer.toString()
+    if code[code.length - 1] is '\\'
+      return backlog = backlog[0...backlog.length - 1]
+    backlog = ''
+    try
+      val = CoffeeScript.eval code, {
+        sandbox,
+        bare: on,
+        globals: on,
+        filename: 'repl'
+      }
+      unless val is undefined
+        process.stdout.write inspect(val, no, 2, enableColours) + '\n'
+    catch err
+      error err
+    repl.prompt()
 
 ## Autocompletion