diff --git a/collects/mzlib/contract.ss b/collects/mzlib/contract.ss
index 9f69097e62..373846be04 100644
--- a/collects/mzlib/contract.ss
+++ b/collects/mzlib/contract.ss
@@ -34,10 +34,14 @@
              lazy-depth-to-look)
  
  (except-out (all-from-out scheme/private/contract)
+             old-define/contract
+             define/contract
+             with-contract
              check-between/c
              string-len/c
              check-unary-between/c)
- (rename-out [string-len/c string/len]))
+ (rename-out [string-len/c string/len]
+             [old-define/contract define/contract]))
 
 ;; from contract-guts.ss
 
diff --git a/collects/scheme/contract.ss b/collects/scheme/contract.ss
index ca55dbf472..617fd07c81 100644
--- a/collects/scheme/contract.ss
+++ b/collects/scheme/contract.ss
@@ -27,6 +27,7 @@ differences from v3:
              check-procedure
              check-procedure/more)
  (except-out (all-from-out "private/contract.ss")
+             old-define/contract
              check-between/c
              check-unary-between/c))
 
diff --git a/collects/scheme/private/contract.ss b/collects/scheme/private/contract.ss
index 000b3191fc..c1ce86a3d1 100644
--- a/collects/scheme/private/contract.ss
+++ b/collects/scheme/private/contract.ss
@@ -12,6 +12,7 @@ improve method arity mismatch contract violation error messages?
 (provide (rename-out [-contract contract])
          recursive-contract
          provide/contract
+         old-define/contract
          define/contract
          with-contract
          current-contract-region)
@@ -57,7 +58,9 @@ improve method arity mismatch contract violation error messages?
                        #,(syntax-position id)
                        #,(syntax-span id))
           #,(format "~s" (syntax->datum id))))
-  
+
+
+
 ;                                                                                                    
 ;                                                                                                    
 ;                                                                                                    
@@ -75,6 +78,68 @@ improve method arity mismatch contract violation error messages?
 ;                                          ;                                                         
 ;                                                                                                    
 
+;; First, we have the old define/contract implementation, which
+;; is still used in mzlib/contract.
+
+(define-for-syntax (old-make-define/contract-transformer contract-id id)
+  (make-set!-transformer
+   (λ (stx)
+     (with-syntax ([neg-blame-str (a:build-src-loc-string stx)]
+                   [contract-id contract-id]
+                   [id id])
+       (syntax-case stx (set!)
+         [(set! id arg)
+          (raise-syntax-error 'define/contract
+                              "cannot set! a define/contract variable"
+                              stx
+                              (syntax id))]
+         [(f arg ...)
+          (syntax/loc stx
+            ((-contract contract-id
+                        id
+                        (syntax->datum (quote-syntax f))
+                        neg-blame-str
+                        (quote-syntax f))
+             arg
+             ...))]
+         [ident
+          (identifier? (syntax ident))
+          (syntax/loc stx
+            (-contract contract-id
+                       id
+                       (syntax->datum (quote-syntax ident))
+                       neg-blame-str
+                       (quote-syntax ident)))])))))
+
+;; (define/contract id contract expr)
+;; defines `id' with `contract'; initially binding
+;; it to the result of `expr'.  These variables may not be set!'d.
+(define-syntax (old-define/contract define-stx)
+  (syntax-case define-stx ()
+    [(_ name contract-expr expr)
+     (identifier? (syntax name))
+     (with-syntax ([contract-id
+                    (a:mangle-id define-stx
+                                 "define/contract-contract-id"
+                                 (syntax name))]
+                   [id (a:mangle-id define-stx
+                                    "define/contract-id"
+                                    (syntax name))])
+       (syntax/loc define-stx
+         (begin
+           (define contract-id contract-expr)
+           (define-syntax name
+             (old-make-define/contract-transformer (quote-syntax contract-id)
+                                                   (quote-syntax id)))
+           (define id (let ([name expr]) name))  ;; let for procedure naming
+           )))]
+    [(_ name contract-expr expr)
+     (raise-syntax-error 'define/contract "expected identifier in first position"
+                         define-stx
+                         (syntax name))]))
+
+
+
 ;; (define/contract id contract expr)
 ;; defines `id' with `contract'; initially binding
 ;; it to the result of `expr'.  These variables may not be set!'d.