diff --git a/pkgs/racket-doc/scribblings/reference/pairs.scrbl b/pkgs/racket-doc/scribblings/reference/pairs.scrbl
index 0a5258e246..13b96ed7ce 100644
--- a/pkgs/racket-doc/scribblings/reference/pairs.scrbl
+++ b/pkgs/racket-doc/scribblings/reference/pairs.scrbl
@@ -667,8 +667,8 @@ Like @racket[assoc], but finds an element using @racket[eq?].
   (assq 'c (list (list 'a 'b) (list 'c 'd) (list 'e 'f)))]}
 
 
-@defproc[(assf [proc procedure?] [lst list?])
-         (or/c list? #f)]{
+@defproc[(assf [proc procedure?] [lst (listof pair?)])
+         (or/c pair? #f)]{
 
 Like @racket[assoc], but finds an element using the predicate
 @racket[proc]; an element is found when @racket[proc] applied to the