Aim: to disclose the perception of nurses working in family planning regarding the vulnerability to sexually transmitted infections (STI) of women who participated in this activity. Method: this is a descriptive and qualitative study that was carried out in a university hospital in Rio de Janeiro, involving nine nurses. Thematic content analysis was used. Results: nurses perceive women as vulnerable as a result of gender inequalities, manifested by their sole responsibility for protection against STIs and contraceptive measures, lack of partner follow-up, and blame of women for unwanted pregnancies. Male domination was attributed to the fact that man wanted to determine the type of protection and/or contraception that would be used in sexual intercourse. In addition, they expressed the difficulty of these women to negotiate safe sex, especially in stable relationships. Conclusion: ISTs are still considered "diseases of the other", influenced by gender inequalities. Traditional family planning actions are not sufficient for the use of preventive measures.