diff --git a/collects/typed-racket/base-env/base-env-numeric.rkt b/collects/typed-racket/base-env/base-env-numeric.rkt
index 5370ed12..f5dd16fb 100644
--- a/collects/typed-racket/base-env/base-env-numeric.rkt
+++ b/collects/typed-racket/base-env/base-env-numeric.rkt
@@ -703,7 +703,8 @@
 [double-flonum? (make-pred-ty -Flonum)]
 [inexact-real? (make-pred-ty -InexactReal)]
 [complex? (make-pred-ty N)]
-[rational? (make-pred-ty -Real)]
+;; `rational?' includes all Reals, except infinities and NaN.
+[rational? (asym-pred Univ B (-FS (-filter -Real 0) (-not-filter -Rat 0)))]
 [exact? (asym-pred N B (-FS -top (-not-filter -Rat 0)))]
 [inexact? (asym-pred N B  (-FS -top (-not-filter (Un -InexactReal -FloatComplex) 0)))]
 [fixnum? (make-pred-ty -Fixnum)]