diff --git a/.travis.yml b/.travis.yml
index a2cfaa5..7b15014 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,6 +13,7 @@ env:
     - RACKET_VERSION=6.1
     - RACKET_VERSION=6.2
     - RACKET_VERSION=6.3
+    - RACKET_VERSION=6.4
     - RACKET_VERSION=HEAD
 
 # You may want to test against certain versions of Racket, without