Adrenocortical tumors in children are extremely rare, accounting only for 0.3-0.4% of all neoplasms in this age. Most frequently they secrete hormones, resulting in virilization, Cushing's syndrome or feminization, while the non-functioning ones are unusual. The authors describe 12 cases observed in 13 years (1976-1989), with a mean age of 5 years. 9 cases showed virilization, 4 presented with Cushing's syndrome and in 5 patients an abdominal mass was palpable. One case was affected by Beckwith-Wiedemann's syndrome. I.V. urography was performed in 8 patients, arteriography in 4 and since 1982 all patients were submitted to abdominal sonography and CT scan or MR imaging. Urinary 17-ketosteroids, 17-hydroxycorticoids and serum testosterone and cortisol were tested in all children. Dexamethasone suppression test was performed in 7. All patients were treated with surgery which seems to be the most suitable treatment, while the real effectiveness of treatment by drug therapy with suppressors of steroidogenesis is not confirmed in children. Histopathological examination showed typical features of adenoma in 5 cases, of adenocarcinoma in 4, while three cases revealed border line forms classified as "atypical adenomas". At the moment 10 patients are alive with a follow-up ranging from 18 months to 14 years, while 2 children with adenocarcinoma are dead.