Drug maintenance treatment (DMT) has only been recently introduced in France (methadone programmes in March 1995, buprenorphine prescriptions in ambulatory medicine in February 1996) in relation to risk reduction policies for HIV infection among intravenous drug users (IDUs). Impact of DMT was assessed in the period of inclusion (October 1995-December 1997) of a French cohort of patients HIV infected through intravenous drug use the MANIF 2000 study). Among the 429 patients, 48.2% were ex-IDUs, 20.3% were active users not in DMT and 31.5% were in DMT. A majority (73.3%) of patients in DMT had persisted in their injection behaviours and their social and psychological characteristics were similar to those of active users not in DMT. Among the 186 active IDUs, those in DMT were more likely to have injected cocaine (42.4%) and buprenorphine or methadone (21.3%) than those who were not (respectively 27.6% and 2.4%), and 23.6% declared direct needle-sharing behaviours during the prior six months. Among younger IDUs (< or = 33 years of age) (n = 100), needle-sharing was associated with polydrug use and cocaine injection but was not significantly reduced by participation in DMT. These results suggest the need for taking into account differences between type of HIV-infected drug users and developing appropriate multidrug maintenance treatment programmes, which may imply adaptations of current dosages of methadone and buprenorphine.