diff --git a/NEWS b/NEWS
index db7149c3..c0cde63c 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,7 @@
  - added new commands "dependson" and "whatdependson" to find out which packages get
    triggered before checkin/request accept.
  - add new "osc build --linksource" option, speeds up esp. image building a lot
+ - add "osc triggerreason" command to show detail reason, why a package got triggered for build
  - Incompatible changes:
    * osc se now prints Project Package, instead of Package Project
      for easier copy&paste.
diff --git a/osc/commandline.py b/osc/commandline.py
index 208f9ae8..16c53e8f 100644
--- a/osc/commandline.py
+++ b/osc/commandline.py
@@ -2737,6 +2737,62 @@ Please submit there instead, or use --nodevelproject to force direct submission.
         print_buildlog(conf.config['apiurl'], *args)
 
 
+    @cmdln.alias('tr')
+    def do_triggerreason(self, subcmd, opts, *args):
+        """${cmd_name}: Show reason why a package got triggered to build
+
+        The server decides when a package needs to get rebuild, this command
+        shows the detailed reason for a package. A brief reason is also stored
+        in the jobhistory, which can be accessed via "osc jobhistory".
+
+        Trigger reasons might be:
+          - new build (never build yet or rebuild manually forced)
+          - source change (eg. on updating sources)
+          - meta change (packages which are used for building have changed)
+          - rebuild count sync (In case that it is configured to sync release numbers)
+
+        usage in package or project directory:
+            osc reason REPOSITORY ARCH
+            osc reason PROJECT PACKAGE REPOSITORY ARCH
+
+        ${cmd_option_list}
+        """
+        wd = os.curdir
+        args = slash_split(args)
+        project = package = repository = arch = None
+        
+        if ( args is None or len(args) < 2):
+            self.print_repos()
+
+        if len(args) == 2: # 2
+            if is_package_dir('.'):
+                 package = store_read_package(wd)
+            else:
+                 raise oscerr.WrongArgs('package is not specified.')
+            project = store_read_project(wd)
+            apiurl = store_read_apiurl(wd)
+            repository = args[0]
+            arch = args[1]
+        elif len(args) == 4:
+            apiurl = conf.config['apiurl']
+            project = args[0]
+            package = args[1]
+            repository = args[2]
+            arch = args[3]
+        else:
+            raise oscerr.WrongArgs('Too many arguments.')
+
+        print apiurl, project, package, repository, arch
+        xml = show_package_trigger_reason(apiurl, project, package, repository, arch)
+        tree = ET.fromstring(xml)
+        reason = tree.find('explain').text
+        print reason
+        if reason == "meta change":
+           print "changed keys:"
+           for package in tree.findall('packagechange'):
+               print "  ", package.get('change'), package.get('key')
+
+
     # FIXME: the new osc syntax should allow to specify multiple packages
     # FIXME: the command should optionally use buildinfo data to show all dependencies
     @cmdln.alias('whatdependson')
diff --git a/osc/core.py b/osc/core.py
index a6b289ad..e05fb0d5 100644
--- a/osc/core.py
+++ b/osc/core.py
@@ -2039,6 +2039,16 @@ def show_project_conf(apiurl, prj):
     return f.readlines()
 
 
+def show_package_trigger_reason(apiurl, prj, pac, repo, arch):
+    url = makeurl(apiurl, ['build', prj, repo, arch, pac, '_reason'])
+    try:
+        f = http_GET(url)
+        return f.read()
+    except urllib2.HTTPError, e:
+        e.osc_msg = 'Error getting trigger reason for project \'%s\' package \'%s\'' % (prj, pac)
+        raise
+
+
 def show_package_meta(apiurl, prj, pac):
     url = makeurl(apiurl, ['source', prj, pac, '_meta'])
     try: