Background Intestinal obstruction is a rare but serious complication after liver transplantation. Adhesions are the most common cause of obstruction in the nontransplantation setting; however, after pediatric liver transplantation unusual causes must be considered. Study Design A prospectively maintained institutional database was analyzed for all reoperations for intestinal obstruction on pediatric liver allograft recipients from 1990 to 2009. Results During the study period, 181 pediatric patients underwent liver transplantation at the study center. The most common indication for transplantation was biliary atresia. Seven patients required reoperation for intestinal obstruction. All 7 patients had abdominal operations before transplantation and 5 of 7 received reduced-size grafts. No patients had adhesive small bowel obstruction. The cause was right-sided diaphragmatic hernia in 4 and post-transplantation lymphoproliferative disorder (PTLD) in 3. Diaphragmatic hernia was demonstrated by chest radiograph in 3 of 4 patients. The fourth was taken to surgery with a presumptive diagnosis of intestinal obstruction and a diaphragmatic hernia was found at exploration. In patients with PTLD causing obstruction, 2 presented with an obstructing mass and the third presented with intussusception. Mean time to reoperation was 29 months after liver transplantation. Patients with diaphragmatic hernia presented earlier post-transplantation than those with PTLD (4.2 ± 2.4 months versus 59.3 ± 54.6 months, respectively; p = 0.0003, Fisher's exact test). Six patients are alive at a median follow-up of 5.8 years. One patient succumbed to recurrent B-cell lymphoma. Conclusions Intestinal obstruction after pediatric liver transplantation is commonly related to what would conventionally be considered unusual causes. A high index of suspicion must be maintained and early operative therapy considered as obstruction because causes such as diaphragmatic hernia and PTLD are unlikely to resolve with conservative measures.