Opsoclonus-myoclonus syndrome is a rare disorder among pediatric patients. The diagnosis is clinical and is characterized by the presence of at least three of the following: opsoclonus, myoclonus, ataxia, irritability and sleep disorders. In over 50 % of cases it is associated with the presence of Neuroblastoma. It is a disorder of immune origin and its treatment is based on immunosuppressants, immunomodulators and tumor resection in cases secondary to Neuroblastoma. Up to 70 % to 80 % of cases may present neurological sequelae, depending on the cause, the initial severity of symptoms and the delay of proper treatment. We present the case of a 2-year-old male with diagnosis of opsoclonus-myoclonus syndrome secondary to a left adrenal Neuroblastoma. Tumor resection and treatment with corticosteroids, immunoglobulin and rituximab were performed.