Opsoclonus is a rare but distinctive disorder of ocular motility, characterized by irregular, continual and conjugated chaotic saccades of the eyes. It is increased with eye closure and fixation, and it persists during sleep. Opsoclonus appears more commonly in children and in half of such cases in association with neuroblastoma. In adults the most frequent causes are idiopathic (50%) and paraneoplastic (20%). Among the second group, different types of tumors involving a wide variety of organs have been reported. Opsoclonus when accompanied by other symptoms of central nervous system involvement (head, appendicular myoclonus and truncal ataxia) constitutes a clinical picture, known as opsoclonus-myoclonus syndrome. We report the case of a young patient affected by renal cell carcinoma associated with opsoclonus-myoclonus syndrome which did not respond to medical therapy but dramatically improved after cancer ablation.