Ovarian neoplasms are unusual in the paediatric age group; the majority of them are of germ cell origin. Malignant epithelial tumours of the ovary occur infrequently in adolescent girls. Ovarian carcinoma in particular is extremely rare before puberty. The authors describe 3 cases of adenocarcinoma of the ovary in premenarchal girls and highlight the unique characteristics of this tumour in this age group.