diff --git a/Makefile b/Makefile
index a980a1d..11cfb5a 100644
--- a/Makefile
+++ b/Makefile
@@ -22,10 +22,14 @@ scsh-blurbs := $(shell find scsh \
                  -maxdepth 2 -mindepth 2 \
                  -name BLURB)
 
-targets := DETAILS COPYING pkg-def.scm
+.PHONY: version-check
+version-check :
+	build/version-check.scm
+
+targets := DETAILS COPYING pkg-def.scm version-check
 
 .PHONY: all
-all : $(targets)
+all : $(targets) check-versions
 
 DETAILS : $(s48-authors) $(s48-blurbs) $(scsh-authors) $(scsh-blurbs) \
           build/details.scm build/dirs.scm build/header.scm
diff --git a/build/version-check.scm b/build/version-check.scm
new file mode 100755
index 0000000..87696df
--- /dev/null
+++ b/build/version-check.scm
@@ -0,0 +1,59 @@
+#! /bin/sh
+exec scsh -o filenames -s "$0" "$@"
+!#
+
+;;; This file is part of the Scheme Untergrund Library. For copyright
+;;; information, see the file COPYING which comes with the
+;;; distribution.
+
+(load "build/common.scm")
+(load "build/dirs.scm")
+
+(define version-re
+  (rx "version"
+      (+ " ")
+      (submatch (+ numeric))
+      (* "." (submatch (+ numeric)))))
+
+(define string->version
+  (lambda (v)
+    (let* ((match (regexp-search version-re v))
+           (major (string->number (match:substring match 1)))
+           (minor (match:substring match 2)))
+      (if minor
+          (list major (string->number minor))
+          (list major)))))
+
+(define ok '#t)
+
+(define check
+  (lambda (dir)
+    (call-with-input-file
+        (string-append dir "/pkg-def.scm")
+      (lambda (port)
+        (let try-again ()
+          (let ((form (read port)))
+            (cond ((eof-object? form)
+                   (error "can't find package version"))
+                  ((and (pair? form)
+                        (eq? (car form) 'define-package))
+                   (let ((name (cadr form))
+                         (version-pkg-def (caddr form))
+                         (version-news
+                          (call-with-input-file
+                              (string-append dir "/NEWS")
+                            (lambda (news-port)
+                              (string->version (read-line news-port))))))
+                     (if (not (equal? version-pkg-def version-news))
+                         (let ()
+                           (display "version mismatch in: ")
+                           (display name)
+                           (newline)
+                           (set! ok '#f)))))
+                  (else
+                   (try-again)))))))))
+
+(for-each check scsh-dirs)
+(for-each check s48-dirs)
+
+(exit (if ok 0 1))
\ No newline at end of file