Sociosexual orientation includes individual differences in sexual attitudes and behaviors, in relation to the extent in which an individual could be sexually active without affective bonds and commitment. Sociosexuality is related to sexual behavior and can speak to the differences between men and women in how they express their sexuality (Simpson & Gangestad, 1991; Hebl & Casi, 1995; Ostovich & Sabini, 2004). This study explores sociosexual orientation and sexual behavior in Mexican adults, in order to identify differences in sociosexual orientation related to biological sex and relationship status. It also assesses the relationship between sociosexual orientation and sexual behavior and to predict sexual behavior from sociosexual orientation. The sample was composed of 209 Mexican adults between 19 and 61 years of age. Thirty-seven percent were male, and 63% were female. Participants answered a standardized Spanish version of the Sociosexual Orientation Inventory (Simpson & Gangestad, 1991) and a Sexual Behavior Inventory developed for the present project (García Rodríguez, 2007). In general, there is great variability in the frequency of each of the sexual behaviors assessed and in the total number of sexual partners. Moreover, participants perceive themselves restricted in their sexual attitudes and behaviors. Men are more permissive and less restricted in attitudes and behaviors than women, and individuals who are dating informally have a higher behavioral sociosexual orientation than those who are living with their partner. Additionally, the higher sociosexuality, the more frequent sexual practices are and the higher the number of sexual partners. Finally, sociosexuality predicts the frequency of sexual practices and the number of lifetime sexual partners.