Our primary goal was to assess health related quality of life (HRQOL) at transplantation and 1 yr after transplantation in pediatric liver transplant patients aged less than 5 years. We conducted a prospective longitudinal study of HRQOL in pediatric liver transplant recipients, aged less than 5 years to define the impact of liver transplantation on HRQOL and identify factors that predict HRQOL after transplantation. The infant toddler health status questionnaire (ITHQ) was completed at the time of listing for liver transplantation and at 6 and 12 months after liver transplantation. The primary outcome measures were the subscale scores that comprise ITHQ. The mean age (+/-s.e.m.) of the enrolled patients (n = 45) at transplantation was 1.4 (+/-1.2) yr. Thirty-eight (84%) of the enrolled patients completed the study. The highest mean baseline scores of 78.6 (+/-3.3) were for global mental health (GlobalMH). ITHQ subscale scores increased steadily after transplantation. The greatest increase was in the first 6 months after transplant. At 1 yr after transplantation, there were significant increases in all of the ITHQ subscale scores except for GlobalMH. ITHQ subscales were similar for patients who received LDLT compared with those who received cadaver donor liver transplantation (CDLT) at baseline and a year after transplant. Time elapsed as transplantation was a significant predictor of functional health in all of the models generated. Scores for general health (GH), global health (GGH), parental time-impact (PT) and parental time-emotion (PE) were higher for male children. Family cohesion (FC) improved with time elapsed since transplant and increased number of inpatient days. HRQOL improves after transplantation in all of our patients irrespective of the donor type. Functional health scores were higher in patients with normal serum bilirubin at 1 yr post-transplant. Assessment of HRQOL should be an integral part of care for liver transplant patients and their caregivers.