The Women's 100m Breaststroke at the 2007 World Aquatics Championships took place on 26 March (prelims & semifinals) and the evening of 27 March (finals) at the Rod Laver Arena in Melbourne, Australia. 72 swimmers were entered in the event, of which 70 swam. Existing records at the start of the event were: * World Record (WR): 1:05.09, Leisel Jones (Australia), 20 March 2006 in Melbourne, Australia. * Championship Record (CR): 1:06.20, Jessica Hardy (USA), Montreal 2005 (25 July 2005)