July 30, 2012
At Showtime's TCA panel earlier today, the network announced that The Big C has been renewed for a final season, which will be the show's fourth.
Four hour-long episodes will conclude the series, which is expected to return in 2013 although no concrete details have been confirmed at this time.
UPDATE (Nov. 8, 2012): Showtime has announced that the four-part conclusion will be considered part of the show's third season - not a fourth season as previously reported.
(Source: TV by the Numbers)