A case of juvenile tumour of the granulosa occurred in a pregnant woman. Outcome was rapidly fatal. These tumours are classed as mesenchyma tumours of the sexual cords of the ovaries. The juvenile form occurs before the age of 30 years in 97% of the cases and has characteristic endocrine and anatomic features. The tumour remains localized in the ovary for a long period and may be treated with conservative surgery to preserve fertility in these young patients. Follow-up is aimed at detecting relapse which may occur early. Prognosis in such cases is very poor. Pregnancy does not modify the prognosis which is generally good.