The aim of this study was to determine if age less than 1 year is a high risk group for orthotopic liver transplantation (OLT). Retrospective analysis was done of patients with liver failure who received OLT. Comparison was made between patients aged < 1 year and > 1 year with regard to survival, allograft survival, hepatic artery thrombosis, and medical status at OLT. Between January 1, 1987 and September 30, 1991, 46 children received OLT. Fifteen (35%) were < 1 year (average age, 7.93 months). Survival in children < 1 year was 80% and children > 1 year was 91%. Allograft survival in children < 1 year was 57% (21 allografts required for 12 survivors) and 78% in children > 1 year (37 allografts required for 29 survivors). Retransplantation was required in 5 of 15 children < 1 year (33%) and in 5 of 29 children (17%) > 1 year. Medical status in children < 1 year was similar to medical status in children > 1 year at the time of transplant. Children with chronic stable liver disease represented 60% of children < 1 year and 60.1% of children > 1 year. Children requiring hospitalization represented 26% of children < 1 year and 29% of children > 1 year. Children in intensive care represented 13% of children < 1 year and 11% of children > 1 year. Survival for all status groups was similar. Hepatic artery thrombosis occurred in one child < 1 year and in 2 children > 1 year. No statistical difference (chi 2 analysis) was found by age between the categories evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)