diff --git a/collects/typed-scheme/types/abbrev.rkt b/collects/typed-scheme/types/abbrev.rkt
index a8203f4e..5ce0ce8a 100644
--- a/collects/typed-scheme/types/abbrev.rkt
+++ b/collects/typed-scheme/types/abbrev.rkt
@@ -176,7 +176,7 @@
 (define -ExactNonnegativeInteger (*Un -ExactPositiveInteger -Zero))
 (define -Nat -ExactNonnegativeInteger)
 
-(define -Byte -Integer)
+(define -Byte -NonnegativeFixnum)