diff --git a/libs/cyclone/foreign.sld b/libs/cyclone/foreign.sld
index 9b562a9f..a136356a 100644
--- a/libs/cyclone/foreign.sld
+++ b/libs/cyclone/foreign.sld
@@ -32,7 +32,7 @@
     (er-macro-transformer
       (lambda (expr rename compare)
         (let ((name (cadr expr))
-              (type (caddr expr)))
+              (type (cddr expr)))
           (unless (eval '(with-handler (lambda X #f) *foreign-types*))
             (write "no foreign type table" (current-error-port))
             (newline (current-error-port))
@@ -49,18 +49,26 @@
                                 (lambda X #f)
                                 (hash-table-ref *foreign-types* (quote ,type-arg))
                                 )))
+               (c-ret-convert #f)
               )
           (when c-type
             (write `(defined c type ,c-type) (current-error-port))
             (newline (current-error-port))
-            (set! type-arg c-type))
+            (set! type-arg (car c-type))
+            (if (= 3 (length c-type))
+                (set! c-ret-convert (caddr c-type))))
 
           ;(for-each
           ;  (lambda (arg)
           ;    (if (not (string? arg))
           ;        (error "c-value" "Invalid argument: string expected, received " arg)))
           ;  (cdr expr))
-          `((lambda () (Cyc-foreign-value ,code-arg ,(symbol->string type-arg))))))))
+
+          (if c-ret-convert
+            `((lambda () (,c-ret-convert (Cyc-foreign-value ,code-arg ,(symbol->string type-arg)))))
+            `((lambda () (Cyc-foreign-value ,code-arg ,(symbol->string type-arg))))
+          )
+          ))))
 
   (define-syntax c-code
     (er-macro-transformer
diff --git a/libs/test-foreign.scm b/libs/test-foreign.scm
index b66a854b..7a00aa43 100644
--- a/libs/test-foreign.scm
+++ b/libs/test-foreign.scm
@@ -12,11 +12,12 @@
 (define *my-global* #f)
 
 (c-define-type my-integer integer)
-(c-define-type my-integer2 integer)
+(c-define-type my-integer-as-string integer string->number number->string)
 
 (test-group "foreign value"
   (test 3 (c-value "1 + 2" integer))
   (test 4 (c-value "2 + 2" my-integer))
+  (test "4" (c-value "2 + 2" my-integer-as-string))
 )
 
 (test-group "foreign code"