diff --git a/lib/async.js b/lib/async.js
index 1edf6b96..86983dd6 100644
--- a/lib/async.js
+++ b/lib/async.js
@@ -5,7 +5,7 @@ var nodeModulesPaths = require('./node-modules-paths.js');
 var normalizeOptions = require('./normalize-options.js');
 var isCore = require('./is-core');
 
-var realpath = typeof fs.realpath.native === 'function' ? fs.realpath.native : fs.realpath;
+var realpath = fs.realpath && typeof fs.realpath.native === 'function' ? fs.realpath.native : fs.realpath;
 
 var defaultIsFile = function isFile(file, cb) {
     fs.stat(file, function (err, stat) {
diff --git a/lib/sync.js b/lib/sync.js
index 65bf4608..932c1ee6 100644
--- a/lib/sync.js
+++ b/lib/sync.js
@@ -5,7 +5,7 @@ var caller = require('./caller.js');
 var nodeModulesPaths = require('./node-modules-paths.js');
 var normalizeOptions = require('./normalize-options.js');
 
-var realpath = typeof fs.realpathSync.native === 'function' ? fs.realpathSync.native : fs.realpathSync;
+var realpath = fs.realpathSync && typeof fs.realpathSync.native === 'function' ? fs.realpathSync.native : fs.realpathSync;
 
 var defaultIsFile = function isFile(file) {
     try {