BACKGROUND Liver transplantation (LT) is recommended for various metabolic diseases, including urea cycle disorders (UCDs). The aim of this study was to determine indications and outcomes of LT for UCDs in the tertiary reference Children's Hospital in Warsaw, Poland. MATERIAL AND METHODS Medical charts of children with UCD who underwent LT between 2008 and July 2016 were retrospectively reviewed. The following parameters were analyzed: symptoms at time of diagnosis, age at diagnosis, age at transplantation, graft characteristics and survival, postsurgical complications, and biochemical and laboratory results before and after transplantation. RESULTS Twelve patients with UCD who underwent LT at a mean age of 5 y (0.5-14 y) received a total of 14 liver grafts. Four children (33%) received a living donor graft, while 8 (68%) got a deceased donor liver graft. A total number of transplanted organs consisted of 9 (64%) whole-liver grafts and 5 (36%) reduced-size grafts. The 30-day post-transplant patient survival rate was 100% and graft survival rate was 93% (13/14). For those with a post-transplant follow-up of at least 1 year (n=10/12), the 1-year patient survival rate was 100% and the graft survival rate was 85.7% (12/14). Median peak of blood ammonia at presentation was 653 (159-2613) µg/dL (normal <80 µg/dl), and median peak of blood glutamine was 1273.2 µmol/l (964-3900 µmol/l). There was 1 episode of hyperammonemia following LT, but it was not due to UCD. Six (50%) patients were diagnosed with some degree of developmental delay/neurological impairment before transplantation, which remained stable or slightly improved after transplantation. Patients without developmental delay before transplantation maintained their cognitive abilities at follow-up. CONCLUSIONS LT leads to eradication of hyperammonemia, withdrawal of dietary restrictions with low-protein diet, and potentially improved neurocognitive development.