Research suggests that stigma toward mental illness extends to evaluations of people with mental disorders as potential romantic partners. However, it is not clear if mental illness functions as a relationship dealbreaker that leads to the rejection of potential mates. The current research consisted of 3 studies that examined mental illness as a relationship dealbreaker and compared its effects to previously established dealbreakers. Study 1 (N = 113) showed that people list an average of 5 mental disorders when asked to report the mental health problems that would lead them to reject a mate. Participants in Study 2 (N = 111) rated specific mental disorders as somewhat or strongly likely to lead them to reject a potential partner. Study 3 (N = 163) showed that people’s willingness to engage in sexual or romantic relationships with an otherwise attractive partner significantly decreased after finding out that the person had a mental disorder. Across the studies, women tended to be more sensitive to dealbreakers than men, especially for short term/sexual relationships, and the pattern of results for mental illness was similar to previously established general dealbreakers. The results of the studies indicate that mental illness does function as a relationship dealbreaker and the conceptualization of social distance toward mental illness should be expanded to include romantic relationships.