The patient was a 72-year-old married woman from whom a recurrent arrhenoblastoma had been removed three time in the course of six years. She was clearly virilized and her voice had become deep. Endocrine studies before removal of the recurrences showed pronounced elevation of the serum testosterone values. The 17-KS values did not as clearly parallel growth of the tumour. Histochemical examination showed moderate 3beta-steroid dehydrogenase activity in limited areas. The histological features were those of so-called intermediate type of arrhenoblastoma with a very scanty tubular component. Histologically the tumour was malignant, but with a relatively low degree of malignancy. Regardless of the treatment there was twice a recurrence of the tumour. The increase of the serum testosterone values during the follow-up period reflected recurrence on of the tumour.