diff --git a/lib/buffer.js b/lib/buffer.js
index f125806622d49d..8f4e34d289fc27 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -276,6 +276,9 @@ function byteLength(string, encoding) {
   if (typeof(string) !== 'string')
     string = String(string);
 
+  if (string.length === 0)
+    return 0;
+
   switch (encoding) {
     case 'ascii':
     case 'binary':