Adrenocortical tumors are very rare in children and the clinical course is not clearly understood. The aim of this study is to review the clinical characteristics and courses of pediatric adrenocortical tumors. The medical records of patients who underwent surgery for primary adrenal tumor at the Department of Surgery, Seoul National University hospital, from Jan. 1986 to Feb. 2006 were reviewed. There were 10 adrenocortical tumor patients; 5 had adrenocortical adenoma and 5 adrenocortical carcinoma. All of the adrenocortical adenomas presented as functioning tumors, i.e., Cushing syndrome or virilization. However, only 2 patients had functioning adrenocortical carcinoma. Median size of adenoma was 5 (3.3-6) cm, and carcinoma 12.5 (6.5-13) cm. Adenomas were smaller than 6 cm and carcinomas were larger than 6.5 cm. Surgical resection alone cured all adrenocortical adenoma patients, and they were all alive without recurrence. Three of 5 adrenocortical carcinoma patients died of tumor recurrence despite radical surgery and chemotherapy. There were 2 long-term survivals for adrenocortical carcinoma, one patient survived 10 years without recurrence until he died of newly developed osteosarcoma, and the other patient is alive without recurrence for 20 years. As the prognosis of pediatric adrenocortical carcinoma is poor, peri-operative aggressive chemotherapy is suggested in addition to radical surgery.