diff --git a/README.md b/README.md
index 420d7c3..55e7bd2 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,8 @@ iWork's Numbers does not appear to support the inline string storage model used
 
 
 ## Sample
+    
+    require 'simple_xlsx'
 
     serializer = SimpleXlsx::Serializer.new("test.xlsx") do |doc|
       doc.add_sheet("People") do |sheet|