AMC has greenlit a fifth season of Mad Men, but extended negotiations with Matthew Weiner — who is reportedly seeking an enormous $30M three-year contract — means the fifth season won’t premiere until March 2012, 17 months after the fourth season finale:
According to sources with knowledge of the negotiations, Weiner had been actually pushing for a shorter gap between Seasons 4 and 5 and had stated that he could get Season 5 produced and delivered on budget for a 2011 premiere. However, I hear AMC’s argument was that it has now 5 original series to accommodate and its next available slot for Mad Men was in March 2012.
More details at Deadline.