Paraneoplastic neurologic syndromes can affect any part of the central or peripheral nervous system. These disorders are uncommon compared to other neurologic complications of systemic cancer, but affected patients often have severe and irreversible neurologic morbidity. Many patients have 1 or more of an ever-growing list of antineuronal or “onconeural” autoantibodies. Because most paraneoplastic syndromes are the presenting feature of the associated neoplasm, neurologists must be able to recognize and diagnose these syndromes promptly. In this article, the author provides an overview of clinical features, autoimmune aspects, and management of patients with known or suspected paraneoplastic disorders.