The VHL gene is a tumor suppressor gene located on chromosome 3p25.3. Mutations in this gene prevent production of the VHL protein and as a result, cells grow and divide uncontrollably to form the tumors and cysts. Germline VHL gene mutations predispose to a variety of tumors, most commonly retinal and cerebellar haemangioblastomas, renal cell carcinoma and phaeochromocytoma. Papillary cystadenomas of the epidididymis are seen in 1026% of men are rarely in broad ligament of the uterus. Mutations in the VHL gene are inherited in an autosomal dominant pattern. A 26 years old female with a known mutation in VHL gene was under surveillance in genetic endocrine clinic. In the last 5 years she had undergone three surgeries for cerebellar haemangiblastomas. She had retinal angiomas and a cervical haemangioblastoma at C2/3. She was known to have a cyst in the right ovary measuring 4.9 cm. This had not changed in size in 4 years and her tumor markers were negative. She presented with 6 month history of feeling tired, amenorrhea and deepening of voice. Her pelvic ultrasound scan showed an increase in the size of right ovarian cyst. It measured 6.8 cm with a lobulated appearance. She had LH of 1.1 IU/l (19), FSH 2.3 IU/l (110) and testosterone of 22.1 nmol/l (0.52). She had a diagnostic laparoscopy and the right ovarian cyst was removed. Her periods started after 11 months of amenorrhea. Her postoperative testosterone was 1.5 nmol/l. Histology of the ovarian cyst showed it to be a clear cell carcinoma. In view of VHL mutation this was thought to be a metastasis from a renal cell carcinoma. This patient had no evidence of Renal cell carcinoma. The most likely diagnosis was testosterone producing clear cell carcinoma of the ovary. The ovarian cyst was documented on the ultrasound scan 4 years ago and was non functioning before changing to a testosterone secreting tumor. Over-expression of hypoxia inducible HIF 1a has been reported in clear cell carcinoma of the ovary. Did the character of the ovarian tumor change because of inducible proteins secondary to over-expression of HIF-1a? To our knowledge this is the first case of testosterone secreting clear cell ovarian tumor in association with VHL.