Inclusion Criteria: - Patients with a confirmed diagnosis of AIDS, with a hematocrit <=30% - preferably dependent on transfusions - having a history of at least a 15% decrease in hematocrit since the beginning of AZT therapy, or have become dependent on transfusions - who are clinically stable for at least 1 month before study entry - females must be at least 1 year post-menopausal, surgically sterile, or practicing an effective method of birth control, and have a negative pregnancy test before study entry.