This study describes the sexual behaviours of women living with HIV, and assesses differences by history of drug use. Its general aim is to contribute in the design of programmes to help people with HIV/AIDS (PWH/A) adopt and maintain safe sexual behaviours. A self-administered questionnaire on sexual and drug use behaviours was distributed to study participants. Between 1997 and 1999, 573 women with HIV infection naive to antiretroviral therapies completed the questionnaire (of whom 234 reported a history of injection drug use (IDU) and were enrolled in the study. Non-IDU women reported fewer sexual partners, both in their lifetime and in the preceding month, than IDU women: 19% of IDU and 4% of non-IDU women reported more than 25 lifetime sexual partners (p < 0.001). Interestingly, 83% of non-IDU women were infected by their regular partners: these women reported the lowest number of sexual partners. No difference emerged between IDU and non-IDU women in terms of number of sexual intercourse in the two weeks preceding the interview or in terms of condom use in the last intercourse (reported, overall, by 54% of these 573 women). Among women who had sex partners at the time of interview, more non-IDU (65%) than IDU (43%) women reported HIV-positive partners (p < 0.001). Overall, these findings stress a marked heterogeneity in the levels of past and recent sexual promiscuity according to history of drug use. It suggests the need to differentiate and individualize messages about self-protection and behaviours that may prevent further spread of HIV infection.