diff --git a/collects/mzlib/pconvert.ss b/collects/mzlib/pconvert.ss
index 31601996e4..b0d7a19994 100644
--- a/collects/mzlib/pconvert.ss
+++ b/collects/mzlib/pconvert.ss
@@ -356,7 +356,11 @@
                                        `(cons ,(recur (mcar expr)) ,(recur (mcdr expr)))))
                                     `(mcons ,(recur (mcar expr)) ,(recur (mcdr expr))))]
                                [(weak-box? expr) `(make-weak-box ,(recur (weak-box-value expr)))]
-                               [(box? expr) `(box ,(recur (unbox expr)))]
+                               [(box? expr)
+                                `(,(if (immutable? expr)
+                                       'box-immutable
+                                       'box)
+                                  ,(recur (unbox expr)))]
                                [(hash-table? expr) 
                                 (let ([contents
                                        (hash-table-map
@@ -372,7 +376,11 @@
                                   (if (null? contents)
                                       `(,constructor)
                                       `(,constructor (list ,@contents))))]
-                               [(vector? expr) `(vector ,@(map recur (vector->list expr)))]
+                               [(vector? expr) 
+                                `(,(if (immutable? expr)
+                                       'vector-immutable
+                                       'vector)
+                                  ,@(map recur (vector->list expr)))]
                                [(symbol? expr) `',expr]
                                [(keyword? expr) `',expr]
                                [(string? expr) expr]
diff --git a/collects/tests/mzscheme/pconvert.ss b/collects/tests/mzscheme/pconvert.ss
index 0ea0a806ed..1d6c2cdc3e 100644
--- a/collects/tests/mzscheme/pconvert.ss
+++ b/collects/tests/mzscheme/pconvert.ss
@@ -163,6 +163,7 @@
                   '(cons 3/2+3/2i empty))
      
      (make-same-test (vector 0 0 0 0 0 0 0 0 0 0) '(vector 0 0 0 0 0 0 0 0 0 0))
+     (make-same-test (vector-immutable 1 2 3 4 5) '(vector-immutable 1 2 3 4 5))
      (make-same-test #t 'true)
      (make-same-test #f 'false)
      
@@ -171,6 +172,7 @@
      (make-same-test (delay 1) '(delay ...))
      (make-same-test (let () (define-struct a (a) #:inspector (make-inspector)) (make-a 3)) '(make-a 3))
      (make-same-test (box 3) '(box 3))
+     (make-same-test (box-immutable 4) '(box-immutable 4))
      (make-pctest null 'empty 'empty 'empty '`() '`() '`() 'empty)
      (make-same-test add1 'add1)
      (make-same-test (void) '(void))