diff --git a/pluralize.js b/pluralize.js
index 1829fc8..feabf3e 100644
--- a/pluralize.js
+++ b/pluralize.js
@@ -283,6 +283,7 @@
     ['themself', 'themselves'],
     ['is', 'are'],
     ['was', 'were'],
+    ['does', 'do'],
     ['has', 'have'],
     ['this', 'these'],
     ['that', 'those'],
diff --git a/test.js b/test.js
index fc84d37..c119cf6 100644
--- a/test.js
+++ b/test.js
@@ -40,6 +40,7 @@ var BASIC_TESTS = [
   ['this', 'these'],
   ['that', 'those'],
   ['is', 'are'],
+  ['does', 'do'],
   ['man', 'men'],
   ['superman', 'supermen'],
   ['ox', 'oxen'],