Leydig cell hyperplasia and Leydig cell tumours of the ovary are rare. We present two cases in which patients had increased blood levels of testosterone and frank hirsutism. Imaging showed minimal abnormalities. After adrenal disease had been ruled out, they underwent a bilateral oophorectomy. One case showed a Leydig cell hyperplasia, the other a Leydig cell tumour. An androgen producing tumour should be excluded in every woman with evidence of hirsutism or frank virilization and markedly elevated testosterone levels. Adrenal disease with androgen hypersecretion can be suspected by detailed clinical, laboratory and radiologic imaging. Although DHEAS has a good sensitivity in the detection of adrenal origin of hyperandrogenism (and hence a good negative predictive value) it is not specific (specificity ranging from 85 to 98%). Imaging of the ovaries can be helpful but does not rule out ovarian disease if normal. Indeed, diffuse stromal Leydig cell hyperplasia and Leydig cell tumours (usually small) may escape imaging and in some cases diagnosis can only be made on pathology. As these clinical entities represent a diagnostic and therapeutic challenge, oophorectomy should be considered in postmenopausal women with hirsutism and elevated testosterone levels, after the exclusion of adrenal causes. The procedure is relatively safe and effective. Follow-up remains indicated.