A chronic coinfection with CMV, EBV etc. has been described in patients with HIV infection; recently a coinfection with other retroviruses has been described too. We have looked for the presence of antibodies to HTLV-I (anti HTLV-I) and to HIV-2 (anti HIV-2) in 135 HIV infected (HIV-positive) subjects living in Rome. They were 100 i.v. drug addicts, 24 homo/bisexuals, 4 partners of HIV-positive patients, 5 polytransfused and 2 without any known risk factor; 32 of them had a full-blown AIDS, 52 had ARC and 51 were symptom-free. Anti HIV, anti HTLV-I and anti HIV-2 were detected with ELISA method and confirmed by Western Blot (W.B.) technique. Antibodies to HTLV-I were found in 14 cases (10.4%) and antibodies to HIV-2 in 12 cases (8.9%). The contemporary presence of anti HIV, anti HTLV-I and anti HIV-2 was not found in any subjects. Our data fail to show a clear relationship among the coinfection with different retroviruses and the various risk factors for HIV infection and the HIV-related clinical picture (AIDS, ARC, etc.).