BACKGROUND Clinical characteristics of acute appendicitis in kidney transplant recipients may be different from those in the general population due to kidney transplant recipient's immunosuppressive state and position change of appendix caused by graft. MATERIAL AND METHODS Clinical characteristics of 10 cases of acute appendicitis among 2880 cases of kidney transplantation were evaluated, including diagnostic rate, location of appendix and complication in kidney transplant recipients. RESULTS Acute appendicitis was suspected in 9 of 10 patients (90%) with acute appendicitis based on clinical and laboratory findings. Five patients (50%) presented with typical migrating pain and 1 patient (10%) had only periumbilical pain. Leukocytosis (WBC >10 000) was present in 8 patients (80%). Radiologic study revealed various locations of appendix relative to grafted kidney. Computed tomography scan was superior to ultrasonography in diagnosis of acute appendicitis. The complication rate was 50%. Complicated patients showed longer duration from symptoms onset to operation (69±48 hours versus. 25±6 hours, P<0.05) and hospital stay (15.4±15 days versus 5.4±1.8 days, P<0.05) than uncomplicated patients. CONCLUSIONS Clinical suspicion and differential diagnosis are needed for kidney transplantation patients with acute appendicitis. Early diagnosis with radiologic study is essential to reduce complications of acute appendicitis.