Objective: Analysis of mortality and risk factors for mortality in the use of renal replacement therapy to correct metabolic disturbances associated with confirmed or suspected inborn errors of metabolism. Study design: A retrospective review of an institutional review board-approved pediatric acute renal failure data base at the University of Michigan. Eighteen patients underwent 21 renal replacement therapy treatments for metabolic disturbances caused by urea cycle defects (n = 14),organic acidemias (n = 5), idiopathic hyperammonemia (n =1), and Reye syndrome (n = 1). Results: There were 14 boys(74%) and 4 girls (26%), with a mean age and weight of 56.2 ±71.0 months and 18.5 ±19.2 kg, respectively, at the initiation of renal replacement therapy. Overall treatment mortality rate was 57.2%(12 of 21 treatments), with 11 of the 18 patients(61.1%) dying before hospital discharge. Two year follow-up on those patients demonstrated that 5 patients (71.4%) remained alive. Initial therapy with hemodialysis was associated with improved survival. Ten treatments (47.6%) required transition to another form of renal replacement therapy to maintain ongoing metabolic control, with a mean duration of 6.1 ±9.8 days.Time to renal replacement therapy > 24 hours was associated with an increased risk of mortality, whereas a blood pressure> 5th percentile for age at the initiation of therapy and the use of anticoagulation were associated with a decreased risk of mortality.Conclusions: Renal replacement therapy can correct the metabolic disturbances that accompany suspected or confirmed inborn errors of metabolism. Our experience demonstrates an approximately 60%mortality rate associated with renal replacement treatment, with more than 70%of survivors living longer than 2 years. Objective: Analysis of mortality and risk factors for mortality in the use of renal replacement therapy to correct metabolic disturbances associated with confirmed or suspected inborn errors of metabolism. Study design: A retrospective review of an institutional review board-approved pediatric acute renal failure data base at the University of Michigan. Eighteen patients underwent 21 renal replacement therapy treatments for metabolic disturbances caused by urea cycle defects (n = 14), organic acidemias (n = 5), idiopathic hyperammonemia (n = 1). Results: There were 14 boys (74%) and 4 girls (26%), with a mean age and weight of 56.2 ± 71.0 months and 18.5 ± 19.2 kg, respectively, at the initiation of renal replacement therapy. Overall treatment Mortality rate was 57.2% (12 of 21 treatments), with 11 of the 18 patients (61.1%) dying before hospital discharge. Two year follow-up on those patients said that 5 patients (71.4%) lived alive. Ten treatments (47.6%) required transition to another form of renal replacement therapy to maintain ongoing metabolic control, with a mean duration of 6.1 ± 9.8 days.Time to renal replacement therapy> 24 hours was associated with an increased risk of mortality, an a blood pressure> 5th percentile for age at the initiation of therapy and the use of anticoagulation were associated with a decreased risk of mortality. Conclusions: Renal replacement therapy can correct the metabolic disturbances that accompanied suspected or confirmed inborn errors of metabolism. Our experience demonstrates an approximately 60% mortality associated with renal replacement treatment, with more than 70% of survivors living longer than 2 years.