There is a broad literature indicating gender differences in cardiovascular heart disease (CHD), with higher risks among men. One possible explanation offered has been gender differences in cardiovascular reactivity. However, this gender gap in morbidity and mortality has been decreasing and attributed by some to the increasing competitive pressure placed on women in the workplace. As a result, it is important to understand situational factors that may influence cardiovascular reactivity during competitive stress. We examined this issue in 46 healthy men and women who competed against a same—or opposite—sex competitor while heart rate (HR) and blood pressure (BP) were measured. Competition outcome (winning or losing) and gender composition of the dyads were balanced and controlled. Consistent with the gender-role conflict perspective, diastolic blood pressure (DBP) reactivity was higher when competing against a man than a woman. In addition, men also showed higher DBP reactivity when losing than when winning, and women demonstrated the opposite pattern. These data suggest that these gender processes may play an important role in understanding response to stressful interpersonal situations.