diff --git a/yum/packages.py b/yum/packages.py
index 4cf42ad..8e69a0f 100644
--- a/yum/packages.py
+++ b/yum/packages.py
@@ -821,6 +821,54 @@ class YumInstalledPackage(YumHeaderPackage):
         fakerepo.cost = 0
         YumHeaderPackage.__init__(self, fakerepo, hdr)
 
+    def verify(self, pattern=[]):
+        """verify that the installed files match the packaged checksum
+           optionally verify they match only if they are in the 'pattern' list
+           returns a tuple """
+        fi = self.hdr.fiFromHeader()
+        results = {} # fn = problem_obj?
+        import pwd
+        import grp
+        for filetuple in fi:
+            #tuple is: (filename, fsize, mode, mtime, flags, frdev?, inode, link,
+            #           state, vflags?, user, group, md5sum(or none for dirs) 
+            (fn, size, mode, mtime, flags, dev, inode, link, state, vflags, 
+                       user, group, csum) = filetuple
+            if pattern:
+                matched = False
+                for p in pattern:
+                    if fnmatch.fnmatch(fn, p):
+                        matched = True
+                        break
+                if not matched: 
+                    continue
+            # do check of file status on system
+            problems = []
+            if not os.path.exists(fn):
+                problems.append('missing')
+            # stat
+            my_st = os.stat(fn)
+            my_user = pwd.getpwuid(my_st[stat.ST_UID])[0]
+            my_group = grp.getgrgid(my_st[stat.ST_GID])[0]
+            #my_mode need to parse the rpmfi mode string of doom
+            if my_st[stat.ST_MTIME] != mtime:
+                problems.append('mtime does not match')
+            if my_group != group:
+                problems.append('group mismatch')
+            if my_user != user:
+                problems.append('user mismatch')
+                
+            # checksum
+            if csum: # don't checksum files that don't have a csum in the rpmdb :)
+                my_csum = misc.checksum('md5', fn)
+                if my_csum != csum:
+                    problems.append('checksum mismatch')
+                if problems:
+                    results[fn] = problems
+                
+        return results
+        
+                             
 class YumLocalPackage(YumHeaderPackage):
     """Class to handle an arbitrary package from a file path
        this inherits most things from YumInstalledPackage because