Studies in adult dialysis patients have identified anemia as a risk factor for patient morbidity and mortality. Limited comparable outcome data are available from children. We used the database from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) to identify patients <18 years of age who initiated dialysis (hemodialysis and peritoneal dialysis) between 1992 and 2001 with no prior history of dialysis or transplantation. A Cox proportional hazards model was used to evaluate the association between anemia (hematocrit <33%) at 30 days post initiation of dialysis and patient mortality. The association between anemia and prolonged hospitalization was also evaluated. Of the 1,942 patients (male 56%), 68% were anemic on day 30. One hundred and seventy-one patient deaths were reported over the 9-year observation period. The multivariate analysis demonstrated anemia to be associated with a 52% higher risk of death (adjusted relative risk 1.52, 95% confidence interval 1.03-2.26, P=0.037). Cardiopulmonary disease was the primary reported cause of death associated with anemia, accounting for 22% of cases. The presence of anemia was also associated with an increased risk for prolonged hospitalization, irrespective of dialysis modality. In conclusion, the presence of anemia 1 month after initiation of dialysis iis associated with an increased risk of prolonged hospitalization and death in pediatric patients. Further studies should ascertain whether anemia per se increases the risk of death or whether it is a marker for other conditions that shorten patient survival, such as chronic inflammation or recurrent infection.