An educational project on sexuality, STDs, and AIDS was conducted for four years with some 500 women. As a result, changes were observed in HIV-related knowledge and attitudes, but not in risk behaviors for infection. This fact motivated the development of a qualitative study to learn the reasons why women failed to incorporate HIV preventive behaviors into their daily lives. Six focus groups were conducted with women who had participated in the educational project. The analysis was thematic. Women were familiar with HIV transmission routes and preventive measures. They admitted not using condoms due to fear of being suspected of infidelity and because this might lead to separation of the couple. Women reported that relationships with their partners had been difficult because of lack of dialogue and that men always had the final word. Although women had information about AIDS, they did not use preventive measures in steady relationships because they did not wield decision-making power. Gender inequality and fidelity were two significant issues related to the increase in AIDS among women.