diff --git a/module_stats.py b/module_stats.py
index 4c8a93f..f3ec11b 100755
--- a/module_stats.py
+++ b/module_stats.py
@@ -6,6 +6,7 @@
 import os
 import datetime
 from optparse import OptionParser
+import subprocess
 
 
 modules = list()
@@ -25,6 +26,7 @@ parser.add_option("--startdate", metavar="YYYY-MM-DD", dest="startdate")
 parser.add_option("--enddate", metavar="YYYY-MM-DD", dest="enddate")
 parser.add_option("--nohpc", action="store_true", default=False, dest="nohpc", help="Exclude hpc* accounts from stats")
 parser.add_option("--printusers", action="store_true", default=False, dest="printusers", help="Print detailed user lists for module usage.")
+parser.add_option("--list-unused", action="store_true", default=False, dest="list_unused", help="List only unused modules.")
 (options, args) = parser.parse_args()
 if options.logdir :
     logdir = options.logdir
@@ -69,18 +71,29 @@ for logfilename in os.listdir(logdir) :
 #        if ' swap' in line :
 #            print line.split()
             
-
 print "-"*78
 print "Module statistics for " + startdate.strftime('%Y-%m-%d') + " - " + enddate.strftime('%Y-%m-%d')
 print "-"*78
-print "{0:60s}{1:>8s}  {2:>8s}".format('module name', '# uses', '# users')
-print "-"*78
-for (v,m) in sorted( ((v,k) for k,v in modulestats.iteritems()), reverse=True) :
-    print "{0:60s}{1:>8d}  {2:>8d}".format(m, v, len(moduleusers[m].keys()))
+if options.list_unused :
+    print "Unused modules:"
+    print "-"*78
+    avail_modules = []
+    p = subprocess.Popen("module -l av " + modulepattern, shell=True, stderr=subprocess.PIPE).stderr
+    for line in p :
+        if modulepattern in line :
+            avail_modules.append(line.split()[0])
+    for module in avail_modules :
+        if not module in modulestats :
+            print module
+else :
+    print "{0:60s}{1:>8s}  {2:>8s}".format('module name', '# uses', '# users')
+    print "-"*78
+    for (v,m) in sorted( ((v,k) for k,v in modulestats.iteritems()), reverse=True) :
+        print "{0:60s}{1:>8d}  {2:>8d}".format(m, v, len(moduleusers[m].keys()))
+        if options.printusers :
+            print moduleusers[m]
+    print "-"*78
+    print "{0:60s}{1:>8d}  {2:>8d}".format('total', total_modules, len(total_users))
     if options.printusers :
-        print moduleusers[m]
-print "-"*78
-print "{0:60s}{1:>8d}  {2:>8d}".format('total', total_modules, len(total_users))
-if options.printusers :
-    print sorted([ (u) for u in total_users ])
+        print sorted([ (u) for u in total_users ])
 print "-"*78