diff --git a/using-s3-source.md b/using-s3-source.md
index 0752e91..92a92c5 100644
--- a/using-s3-source.md
+++ b/using-s3-source.md
@@ -61,7 +61,7 @@ Or set AWS access id, secret and session token explicitly.
     - s3://bucket3/path_to_gems_dir/
     - s3://bucket4/
     - https://rubygems.org/
-    :s3_source:
+    s3_source:
       :bucket1:
         :provider: env
       :bucket2: