A stromal luteoma is an uncommon ovarian tumour in post-menopausal women, which presents rarely with hyperandrogenism and virilization. We present the case of a 64-year-old woman referred for evaluation of virilization which had developed over 5 years. Testosterone, FSH and LH were markedly inhibited following the administration of a GnRH analogue, suggesting a gonadotrophin dependent, testosterone secreting ovarian tumour, which could not be localized with imaging techniques. Surgery revealed normal sized ovaries with no apparent lesions, but microscopic examination showed a small stromal luteoma in the right ovary and severe stromal hyperthecosis in the adjacent and contralateral ovarian stroma. We conclude that stromal luteoma is an uncommon cause of virilization in post-menopausal women. This case illustrates, to our knowledge for the first time, that a stromal luteoma is not autonomous but is gonadotrophin dependent.