That will run every hour at the 15th minute. For every 15 mins, use 15,30,45,59 * * * * command More here: http://en.wikipedia.org/wiki/Crontab # Use the hash sign to prefix a comment # +---------------- minute (0 - 59) # | +------------- hour (0 - 23) # | | +---------- day of month (1 - 31) # | | | +------- month (1 - 12) # | | | | +---- day of week (0 - 7) (Sunday=0 or 7) # | | | | | # * * * * * command to be executed