Malignant ovarian tumors are very rare during childhood and adolescence where their incidence is approximately 0.71 per 100,000. We reviewed the symptoms, histologic subtypes, diagnostic evaluation and management of ovarian tumours in children and adolescents with emphasis on malignant tumours. The histology of these tumours is complex and their diagnosis frequently poses problems. Surgery and chemotherapy yield high cure rates in patients with malignant germ cell tumours whereas prognosis is poorer in ovarian carcinomas. Elucidation of the mechanisms underlying the pathogenesis of ovarian tumors might further improve the management of these patients.