Peripheral neurological paraneoplastic syndromes include some of the most convincingly demonstrated autoimmune disorders. Though rare, they are an important cause of neurological morbidity and mortality, often signaling the presence of an occult tumor. Covered under this heading are disorders of peripheral nerves and nerve roots (neuropathies and radiculopathies), the neuromuscular junction (myasthenic syndromes) and muscle (myopathic syndromes). Electrophysiological studies, laboratory screening for circulating autoantibodies, cerebrospinal fluid analysis and muscle or sensory nerve biopsies in selected cases aid the clinician in making the neurological diagnosis. Discrete components of the nervous system such as the neuromuscular junction's calcium channels (Lambert-Eaton myasthenic syndrome) or acetylcholine receptors (myasthenia gravis) are the targets of immunoaggression. Treatment directed at the tumor and the demonstrable or presumed immunological pathophysiology, assisted by supportive medical care and symptomatic drug therapies, offers the best chance for clinical improvement.