Objective:To investigate the clinical characteristics, diagnosis and treatment of acute appendicitis after orthotopic liver transplantation (OLT) in adult. 
Methods:The clinical data of 4 liver transplant recipients with acute appendicitis after transplantation and 4 patients with misdiagnosed appendicitis from Jan 2000  to Dec 2007 were studied retrospectively.
Results:The incidence rate of acute appendicitis after OLT was 0.49%（4/817）in our single center. The 4 patients complained of right lower quadrant abdominal pain and fever on the 8th, 13th, 11th and 9th day post-transplantion, respectively. Tenderness in right lower abdomen and rebound tenderness were presented, and white blood cells counts was elevated. Appendicetomy was perfomed in 2 cases on the 1st day and in 2 cases on the 2nd day of the onset of symptoms. No appendicular perforation was found during the operation. The patients recovered and well during followed up for 84m, 62m, 40m and 29m, respectively. The other 4 misdiagnosed patients were diagnosed with duodenal diverticulum perforation in 1 case, jejunum perforation in 1 case and bile leakage in 2 cases after exploratory laparotomy.
Conclusions:The incidence rate of acute appendictis after OLT is low, and should be differentiaed from other surgical complications, such as gastrointestinal perforation and bile leakage. Appendicetomy should be performed as early as possible in patients with definite diagnosis.