Childhood adrenocortical tumours (ACT) constitute only about 0.2% of all paediatric malignancies. However, the incidence of ACT varies across geographic regions and is remarkably high in southern Brazil. At presentation, most children show signs and symptoms of virilisation, which may be accompanied by manifestations of the hypersecretion of other adrenal cortical hormones. Fewer than 10% of patients with ACT show no endocrine syndrome at presentation; these are often older children and adolescents. ACT is commonly associated with constitutional genetic abnormalities, particularly mutations of the P53 gene. Histological features are used to classify the tumours as adenomas or carcinomas; however, the distinction between these two subtypes is often difficult. The extent of disease is best evaluated by computed tomography or magnetic resonance imaging; the role of positron-emission tomographic scans has not been defined. Cure of ACT requires complete tumour resection. The role of chemotherapy or radiotherapy has not been established, although definitive responses to several anticancer drugs have been documented. Among patients who undergo complete tumour resection, favourable prognostic factors include age <4 years, smaller tumour size, signs of virilisation alone at presentation, and adenomatous tumour histology. Some children with ACT show abnormalities of growth and development at the time of presentation, but these usually resolve after surgery.