diff --git a/collects/tests/racket/cat.rkt b/collects/tests/racket/cat.rkt
new file mode 100644
index 0000000000..806957b820
--- /dev/null
+++ b/collects/tests/racket/cat.rkt
@@ -0,0 +1,24 @@
+#lang racket
+
+;; Implements a "cat.exe" executable under Windows for the 
+;; "subprocess.rktl" test.
+
+(require racket/port)
+
+(define files
+  (command-line
+   #:args
+   file
+   file))
+
+(if (null? files)
+    (copy-port (current-input-port)
+	       (current-output-port))
+    (for ([f (in-list files)])
+       (if (equal? f "-")
+	   (copy-port (current-input-port)
+		      (current-output-port))
+	   (if (file-exists? f)
+	       (call-with-input-file* f (lambda (in) (copy-port in (current-output-port))))
+	       (raise-user-error 'cat "bad file ~a" f)))))
+(flush-output)
diff --git a/collects/tests/racket/subprocess.rktl b/collects/tests/racket/subprocess.rktl
index 2cd91777b2..5d0d0d040e 100644
--- a/collects/tests/racket/subprocess.rktl
+++ b/collects/tests/racket/subprocess.rktl
@@ -8,7 +8,11 @@
 (define self
   (parameterize ([current-directory (find-system-path 'orig-dir)])
     (find-executable-path (find-system-path 'exec-file) #f)))
-(define cat (find-executable-path "cat" #f))
+(define cat (find-executable-path 
+	     (if (eq? 'windows (system-type)) 
+		 "cat.exe"
+		 "cat")
+	     #f))
 (define tmpfile (build-path (find-system-path 'temp-dir) "cattmp"))
 (define tmpfile2 (build-path (find-system-path 'temp-dir) "cattmp2"))
 
diff --git a/src/racket/src/port.c b/src/racket/src/port.c
index f0ef6029bd..012fc70638 100644
--- a/src/racket/src/port.c
+++ b/src/racket/src/port.c
@@ -7559,8 +7559,43 @@ static void close_subprocess_handle(void *sp, void *ignored)
   CloseHandle(subproc->handle);
 }
 
+static void CopyFileHandleForSubprocess(int *hs, int pos)
+{
+  HANDLE h2;
+  int alt_pos = (pos ? 0 : 1);
+
+  if (DuplicateHandle(GetCurrentProcess(),
+		      (HANDLE)hs[pos],
+		      GetCurrentProcess(),
+		      &h2,
+		      0,
+		      TRUE,
+		      DUPLICATE_SAME_ACCESS)) {
+    hs[pos] = (int)h2;
+    hs[alt_pos] = 1;
+  } else {
+    hs[alt_pos] = 0;
+  }
+}
+
+static void CloseFileHandleForSubprocess(int *hs, int pos)
+{
+  int alt_pos = (pos ? 0 : 1);
+  if (hs[alt_pos]) {
+    CloseHandle((HANDLE)hs[pos]);
+  }
+}
+
+#define mzCOPY_FILE_HANDLE(array, pos) CopyFileHandleForSubprocess(array, pos)
+#define mzCLOSE_FILE_HANDLE(array, pos) CloseFileHandleForSubprocess(array, pos)
+
 #endif /* WINDOWS_PROCESSES */
 
+#ifndef mzCOPY_FILE_HANDLE
+# define mzCOPY_FILE_HANDLE(array, pos) /* empty */
+# define mzCLOSE_FILE_HANDLE(array, pos) /* empty */
+#endif
+
 /*********** All: The main system/process/execute function *************/
 
 static Scheme_Object *subprocess(int c, Scheme_Object *args[])
@@ -7616,6 +7651,7 @@ static Scheme_Object *subprocess(int c, Scheme_Object *args[])
       else if (SAME_OBJ(op->sub_type, fd_output_port_type))
 	from_subprocess[1] = ((Scheme_FD *)op->port_data)->fd;
 # endif
+      mzCOPY_FILE_HANDLE(from_subprocess, 1);
 #endif
     } else
       scheme_wrong_type(name, "file-stream-output-port", 0, c, args);
@@ -7639,6 +7675,7 @@ static Scheme_Object *subprocess(int c, Scheme_Object *args[])
       else if (SAME_OBJ(ip->sub_type, fd_input_port_type))
 	to_subprocess[0] = ((Scheme_FD *)ip->port_data)->fd;
 # endif
+      mzCOPY_FILE_HANDLE(to_subprocess, 0);
 #endif
     } else
       scheme_wrong_type(name, "file-stream-input-port", 1, c, args);
@@ -7662,6 +7699,7 @@ static Scheme_Object *subprocess(int c, Scheme_Object *args[])
       else if (SAME_OBJ(op->sub_type, fd_output_port_type))
 	err_subprocess[1] = ((Scheme_FD *)op->port_data)->fd;
 # endif
+      mzCOPY_FILE_HANDLE(err_subprocess, 1);
 #endif
     } else
       scheme_wrong_type(name, "file-stream-output-port", 2, c, args);
@@ -7736,23 +7774,33 @@ static Scheme_Object *subprocess(int c, Scheme_Object *args[])
   /*          Create needed pipes         */
   /*--------------------------------------*/
 
-  if (!inport && PIPE_FUNC(to_subprocess, 1 _EXTRA_PIPE_ARGS))
+  if (!inport && PIPE_FUNC(to_subprocess, 1 _EXTRA_PIPE_ARGS)) {
+    if (outport) { mzCLOSE_FILE_HANDLE(from_subprocess, 1); }
+    if (errport) { mzCLOSE_FILE_HANDLE(err_subprocess, 1); }
     scheme_raise_exn(MZEXN_FAIL, "%s: pipe failed (%e)", name, errno);
+  }
   if (!outport && PIPE_FUNC(from_subprocess, 0 _EXTRA_PIPE_ARGS)) {
     if (!inport) {
       MSC_IZE(close)(to_subprocess[0]);
       MSC_IZE(close)(to_subprocess[1]);
+    } else {
+      mzCLOSE_FILE_HANDLE(to_subprocess, 0);
     }
+    if (errport) { mzCLOSE_FILE_HANDLE(err_subprocess, 1); }
     scheme_raise_exn(MZEXN_FAIL, "%s: pipe failed (%e)", name, errno);
   }
   if (!errport && PIPE_FUNC(err_subprocess, 0 _EXTRA_PIPE_ARGS)) {
     if (!inport) {
       MSC_IZE(close)(to_subprocess[0]);
       MSC_IZE(close)(to_subprocess[1]);
+    } else {
+      mzCLOSE_FILE_HANDLE(to_subprocess, 0);
     }
     if (!outport) {
       MSC_IZE(close)(from_subprocess[0]);
       MSC_IZE(close)(from_subprocess[1]);
+    } else {
+      mzCLOSE_FILE_HANDLE(from_subprocess, 1);
     }
     scheme_raise_exn(MZEXN_FAIL, "%s: pipe failed (%e)", name, errno);
   }
@@ -7892,14 +7940,20 @@ static Scheme_Object *subprocess(int c, Scheme_Object *args[])
       if (!inport) {
 	MSC_IZE(close)(to_subprocess[0]);
 	MSC_IZE(close)(to_subprocess[1]);
+      } else {
+	mzCLOSE_FILE_HANDLE(to_subprocess, 0);
       }
       if (!outport) {
 	MSC_IZE(close)(from_subprocess[0]);
 	MSC_IZE(close)(from_subprocess[1]);
+      } else {
+	mzCLOSE_FILE_HANDLE(from_subprocess, 1);
       }
       if (!errport) {
 	MSC_IZE(close)(err_subprocess[0]);
 	MSC_IZE(close)(err_subprocess[1]);
+      } else {
+	mzCLOSE_FILE_HANDLE(err_subprocess, 1);
       }
       scheme_raise_exn(MZEXN_FAIL, "%s: fork failed (%e)", name, fork_errno);
       return scheme_false;
@@ -8003,18 +8057,24 @@ static Scheme_Object *subprocess(int c, Scheme_Object *args[])
   if (!inport) {
     mzCLOSE_PIPE_END(to_subprocess[0]);
     out = NULL;
-  } else
+  } else {
+    mzCLOSE_FILE_HANDLE(to_subprocess, 0);
     out = scheme_false;
+  }
   if (!outport) {
     mzCLOSE_PIPE_END(from_subprocess[1]);
     in = NULL;
-  } else
+  } else {
+    mzCLOSE_FILE_HANDLE(from_subprocess, 1);
     in = scheme_false;
+  }
   if (!errport) {
     mzCLOSE_PIPE_END(err_subprocess[1]);
     err = NULL;
-  } else
+  } else {
+    mzCLOSE_FILE_HANDLE(err_subprocess, 1);
     err = scheme_false;
+  }
 
   /*--------------------------------------*/
   /*        Create new port objects       */