diff --git a/offlineimap/init.py b/offlineimap/init.py
index 3ff343e..8d2df12 100644
--- a/offlineimap/init.py
+++ b/offlineimap/init.py
@@ -102,6 +102,13 @@ def startup(versionno):
 
     lock(config, ui)
 
+    try:
+        pidfd = open(config.getmetadatadir() + "/pid", "w")
+        pidfd.write(os.getpid())
+        pidfd.close()
+    except:
+        pass
+
     try:
         if options.has_key('-l'):
             sys.stderr = ui.logfile