This paper suggests that women are at a significant disadvantage in close U.S. Congressional races compared to men. Previous political science literature has argued that women do not have a disadvantage in U.S. politics. Much of this previous literature argues that the apparent disadvantage women face in elections comes from the fact that there are fewer incumbent women in Congress and that men are continuing to win seats in Congress due to incumbency. This paper uses a Regression Discontinuity Design to test how repeat candidates perform in elections, looking at the differences between women and men and the differences between incumbents and challengers. Studying candidates in the U.S. House from 1968 to 2008, this paper finds that when examining candidates in the most competitive races and controlling for the candidate’s success in the previous election, women do not compete as well as their male counterparts. The results of this paper suggest that women challengers (women not running as incumbents) are especially disadvantaged compared to male challengers and that women incumbents in close election races are also at a disadvantage compared to similar male candidates. The paper also found that these disadvantages were strongest in close elections and not apparent when including candidates who did not run close races. Overall, these findings suggest that unless they are entrenched incumbents, women do not perform as well as men do in elections. This finding supports the fact that America lags behind the rest of the world in the percentage of women serving in its national legislature.