This study investigated the extent to which women's and men's relationship satisfaction within couples is similarly or differently affected by becoming a parent and the extent to which changes in work hours and hours spent on household labor affect a person's own and his or her spouse's relationship satisfaction across the transition to parenthood. The authors conducted longitudinal dyadic analyses, based on 12 waves of the British Household Panel Study (BHPS). They selected 689 couples who remained together during the period of observation and who were employed, childless, and living with their partner (of which 28% married) at the first moment of observation. The results revealed that relationship satisfaction of both members in a couple changed in tandem. Although work hours and household labor had some effect on people's own and their spouse's relationship satisfaction, these factors did not account for the U-shaped relationship satisfaction pattern associated with the transition to parenthood. (Contains 3 tables and 1 figure.)