diff --git a/collects/ffi/unsafe.rkt b/collects/ffi/unsafe.rkt
index 669eaffabc..83f54aecd7 100644
--- a/collects/ffi/unsafe.rkt
+++ b/collects/ffi/unsafe.rkt
@@ -1105,7 +1105,10 @@
           (if (cpointer? p)
             (and p (if (cpointer-has-tag? p t) p (error* p)))
             (error* p))))
-      (make-ctype (or ptr-type _pointer)
+      (make-ctype (cond
+                   [(and nullable? ptr-type) (_or-null ptr-type)]
+                   [ptr-type]
+                   [else _pointer])
         ;; bad hack: `if's outside the lambda for efficiency
         (if nullable?
           (if scheme->c
diff --git a/collects/tests/racket/cstruct.rktl b/collects/tests/racket/cstruct.rktl
index f5eb8a9046..2a99547ef5 100644
--- a/collects/tests/racket/cstruct.rktl
+++ b/collects/tests/racket/cstruct.rktl
@@ -20,6 +20,8 @@
       (test '(4 5 6) tri->list tv2)
       (test '(4 5 6) tri->list* tv2)
       (test '(7 8 9) tri->list* (list*->tri '(7 8 9)))
+      (test #f cast #f _tri-pointer/null _pointer)
+      (test #f cast #f _pointer _tri-pointer/null)
       (test #t tri? tv)
       (test #f tri? 'tv)
       (test #f tri? (cast 1 _intptr _pointer))
@@ -40,6 +42,8 @@
       (test #f tri? 'tv)
       (test #f tri? (cast 1 _intptr _pointer))
       (q-more qv)
+      (test #f cast #f _quad-pointer/null _pointer)
+      (test #f cast #f _pointer _quad-pointer/null)
 
       (define-cstruct _quint ([pre _quad]
                               [r _float]))