Although invasive cervical cancer (ICC) has been included among the AIDS-defining conditions since 1993, it remains controversial whether HIV infection increases the risk of developing such neoplasm. In this study, ICC risk was longitudinally investigated among 1,340 HIV-positive intravenous drug user (IDU), 811 HIV-negative IDU, and 801 HIV-positive heterosexual women. These women, aged 15-49 years, were followed up at the Italian HIV Seroconverter Study, at the San Patrignano Community (Rimini, North Italy), and in South-eastern France (the DMI-2 study). The number of observed cases of ICC was compared with the expected one, based on ICC incidence rates among women of the same age in the general population of Italy or France, and standardized incidence ratios (SIR) were computed; 9,070 person-years of observation were accumulated among HIV-positive women and 2,310 among HIV-negative ones. Ten cases of ICC were diagnosed among HIV-positive women (SIR = 12.8): ICC risk was apparently higher among HIV-positive IDU (SIR = 16.7) than among heterosexual women (SIR = 6.7). No cases of ICC were diagnosed among HIV-negative IDU women admitted to the San Patrignano Community (0.15 cases were expected). Our findings confirm previous suggestions showing an increased risk of ICC among HIV-infected women and have important implications at the individual and public health levels.