Women's mate choice criteria were examined experimentally in the contexts of long-term and extra-pair mateship scenarios. In long-term mateships, women may benefit by pairing with males who provide material resources and assistance in child rearing. In contrast, in extra-pair mateships, women may benefit in other ways, with such benefits outweighing the potential costs imposed by a primary mate who discovers the relationship. One benefit, or evolutionary function, of extra-pair mateships may be to replace a primary mate, in which case mate preferences should look similar across long-term and extra-pair contexts. However, another function of extra-pair mateships may be to obtain high quality gametes (Le., “good genes”), in which case women should be differentially attracted to cues of heritable phenotypic quality, such as physical attractiveness. By using detailed verbal and pictorial descriptions of men and requiring participants to trade off physical attractiveness for good character (i.e., being a good cooperator and parent), it was possible to determine whether women's criteria for partners varied across experimental contexts. Findings suggest that extra-pair mateships may have served the evolutionary function of obtaining “good genes,” because attractiveness was more important in extra-pair mateships to the detriment of good character. This effect was maintained even when characteristics of the female participants (age, parity, marital experience) were covaried. In addition, the preference for physical attractiveness was specific to the sexual context; it did not generalize, in a second experiment, to choices among short-term male coworkers.