Two studies examined which traits males and females desire in partners at various levels of relationship development in an attempt to integrate evolutionary models (which emphasize sex differences) and social exchange models (which emphasize self-appraisals). In Study 1, male and female students specified their minimum criteria on 24 traits for a date, sexual partner, exclusive dating partner, marriage partner, and 1-night sexual liaison. They also rated themselves on the same dimensions. Sex differences were greatest for casual sexual liaisons, with men's criteria being consistently lower than women's. Men's self-ratings were generally less correlated with their criteria for a 1-night stand, as well. Study 2 replicated the findings of Study 1, adding several modifications, including a measure of Ss' sex typing. Sex typing had few effects. The advantages of combining social psychological and evolutionary perspectives are discussed.