A questionnaire was administered to 160 injection drug users, enrolled in a methadone or buprenorphine maintenance treatment program at their local Drug Addiction Treatment Service (Ser.T), in order to measure their attitudes and risk-taking behaviours towards HIV. Despite being on a maintenance treatment program, almost half of the interviewed subjects (43,75%) declared that they continued to use drugs, occasionally (15,62%), monthly (6,25%), weekly (10,62%) or daily (11,25%). Moreover, a high rate of risk-taking behaviour for HIV was found among the interviewed drug addicts, such as sharing of injection equipment (39,40%), irregular condom use (15,00%) and unprotected sex with casual partners (9,40%). When asked about which interventions they would consider to be most effective for HIV prevention, more than half of the interviewed subjects (58,12%) indicated qualified information regarding HIV transmission, while a lower but not negligible proportion of subjects thought the free distribution of syringes (21,25%) or condoms (20,63%) would be most effective. In contrast to other studies, our results show that pharmacological maintenance treatments may not have a role in preventing HIV infection among injection drug users. On the other hand, our results suggest that the presence, within the Ser.T team, of professional educators specialized in the prevention of sexually transmitted diseases may be more useful.