Patients are enrolled in one of two study groups. The treatment group consists of HIV-1 seropositive patients with hemophilia A or B who are protease-inhibitor naive. The laboratory control group consists of HIV-1 seropositive patients with hemophilia A who are on a stable, triple-combination antiretroviral regimen. Patients in the treatment group receive indinavir sulfate plus two of the following NRTIs: zidovudine (ZDV), didanosine (ddI), zalcitabine (ddC), stavudine (d4T), or lamivudine (3TC). Patients in the treatment group preferably are naive to one or both of the NRTIs. Patients in the laboratory control group continue on their stable triple antiretroviral regimen consisting of a protease inhibitor plus two NRTIs. Patients in the control group are not provided antiretroviral medications as part of this study. Patients in the treatment group are evaluated by physical examination, safety laboratory tests, CD4 cell counts, and viral load on Day 1 and at Weeks 2, 4, 8, and 12 and then every 8 weeks through Week 52. Patients in the control group are evaluated by physical examination, safety laboratory tests, CD4 cell counts, and viral load on Day -1 and at Week 12. All patients receive their usual factor concentrate infusion over a 10-minute period on Day -1 and at Week 12 to estimate factor VIII (or IX) recovery and half-life. Blood samples are taken prior to infusion and 30 minutes and 1, 3, 6, 9, 12, and 24 hours after infusion. All patients are required to keep a daily log documenting bleeding episodes and use of factor VIII (or IX) throughout the study.