Simple parathyroid cysts are rare; only about 200 cases have been reported in the literature. The diagnosis was facilitated recently by parathyroid hormone assay of the cyst fluid. Standard treatment consists of percutaneous aspiration of the cyst and surgical excision for recurrent lesions. Sclerotherapy of recurrent lesions was described in two cases and results were promising. The authors report a new case of recurrent nonfunctioning parathyroid cyst in a 34-year-old female, with complete resolution after ethanol sclerosis and no recurrence for 15 months of follow-up. Ethanol sclerotherapy is recommended as a simple and safe treatment for recurrent parathyroid cysts.