Objective: The study assessed the relationship between a history of child abuse, nonadherence to medications, and medical outcome in children who had a liver transplant. Method: Abuse history for children and adolescents ages 8 to 21 who underwent a liver transplantation at Mount Sinai Medical Center in New York was obtained in interviews in 2002. Adherence to tacrolimus was assessed from January 1 to December 31, 2003 by computing the SD of a series of medication blood levels for each patient. Biopsy-proven rejection episodes, degree of fluctuation of alanine aminotransferase (ALT), and maximal ALT levels were recorded as indicators of medical outcome. Results: Of 72 eligible patients, 56 were evaluated. Five had documented abuse. Abused children were less adherent to their medication regimen (p = 0.02; 95% confidence interval [CI] -2.66 to -0.24), had poor disease control (higher maximal ALT, p less than 0.01; 95% CI -613.72 to -249.55), had greater fluctuation in ALT levels (p less than 0.01; 95% CI -151.19 to -65.91), and suffered more biopsy-proven rejection episodes (two episodes in the abused cohort versus none in the rest) in 2003. Conclusions: A history of child abuse is a significant risk factor for poor outcome post-transplantation and should be evaluated routinely. Adherence to medications can be a target for intervention in patients with a history of abuse. (Contains 5 tables and 1 figure.)