The objective is to present risky sexual behaviors that can lead to contracting sexually transmitted infections (STIs). In San Luis Potosí, Mexico, a universe of 77 men with active sexual life was studied; a self-administered questionnaire with four sections was applied: initiation of sexual intercourse, sexually transmitted diseases, preventive actions and number of sexual partners. To measure sexual behavior, two scales were designed, an ordinal one to observe different levels, a nominal one for the presence or absence of risky sexual behaviors. Some results obtained show that 87.1% had their first sexual intercourse at age 18 or earlier, 53.2% always used condoms, 93.5% had their first sexual intercourse with women and 6.5% with men, and 63.7% engaged in risky sexual behavior. One of the conclusions is that the majority of males in this study engaged in one or more risky sexual behaviors that can lead to contracting HPV and other sexually transmitted diseases