A randomized, double-blind, placebo-controlled, multicenter trial was performed to assess the safety and efficacy of subcutaneous recombinant erythropoietin (EPO) in peritoneal dialysis patients. Seventy-eight patients were randomized to receive EPO and 74 received placebo during the first 12 wk. After this, placebo patients with hematocrit less than 32% entered the EPO maintenance phase along with the initial EPO patients. Hematocrit rose significantly in the EPO group from 23.8 to 32% after 6 wk, and this was sustained at 33.7% at 12 wk. In the placebo group, the prestudy hematocrit was 23.8% as well, and no significant change in hematocrit occurred over 12 wk. Concomitant with the rise in hematocrit, transfusion requirements fell only in the EPO group. Eighty-eight percent of patients receiving EPO had their anemia ameliorated by Week 12 of the study. There was a wide range of dosage requirements during the maintenance phase, ranging from 8,000 U thrice weekly to 4,000 U every other week. Adverse events after EPO were similar to those seen in hemodialysis patients given this agent, with hypertension developing or worsening in 55% of EPO patients during the initial 12 wk of therapy. Blood pressure was more likely to rise in patients with hypertension before receiving EPO. EPO is safe and effective in peritoneal dialysis patients, as it is in hemodialysis patients. Other than a rise in blood pressure, which is manageable with antihypertensives and ultrafiltration with dialysis, no serious side effects are seen. The optimal target hematocrit, effects of anemia improvement on quality of life, and end-organ (heart, brain) effects of anemia improvement in this patient population require further study.