Hyperandrogenism in females usually results from ovarian or adrenal pathology. We present a case of virilizaton due to very rare bilateral ovarian diffuse interstitial proliferation of Leydig cells with no tumour or hilar cell hyperplasia identified. Interestingly, the case was further complicated by the finding of high levels of testosterone in one adrenal vein on selective venous sampling (SVS), resulting in an unnecessary unilateral adrenalectomy. Further sampling found high levels also in the ovarian veins, and the condition was finally cured by bilateral oophorectomy.