The opsoclonus-myoclonus syndrome is a rare entity as a paraneoplastic disorder usually associated to neuroblastoma in children and breast cancer or oat-cell lung carcinoma in adults. The association of opsoclonus-myoclonus syndrome and ovarian carcinoma is very unusual, to our knowledge there is only two cases reported in the literature. In both of them the opsoclonus-myoclonus syndrome preceded the neoplasy, improving with its treatment. In our patient opsoclonus began after ovarian cancer diagnosis, after chemotherapy and radiotherapy, improving with corticoid and clonazepan therapy.