Sensory neuronopathy is a well-recognized remote effect of carcinoma. We report the clinical and electrodiagnostic evolution of a sensory neuronopathy in a patient with carcinoma of the lung. Serial electrophysiologic studies suggest transformation from normal peripheral nerve function through early posterior root involvement to absent sensory nerve function. Diffuse motor conduction abnormalities occurred late in the disease, perhaps reflecting motor axon changes associated with disuse.