We followed 42 patients with clinically defined pure sensory neuropathy of acute or subacute onset for 2 to 35 years. The symptoms began in the upper limbs in 23 patients, in the lower limbs in 13, symmetrically in all 4 limbs in 4, and the face was 1st affected in 2. For 19 patients, the symptoms began asymmetrically. Electrophysiologic testing typically showed absence of sensory potentials. Spinal fluid was usually acellular with a normal protein level. Sural nerve biopsy in 22 patients showed loss of large myelinated fibers and axonal atrophy without inflammation. Six of the patients died: 4 of unrelated causes and 2 of subdural hemorrhages. Only 2 patients had severe functional impairment. Twenty-two had significant sensory deficit but were able to carry out most of their usual activities. In 8, the symptoms had resolved completely. The acute, often focal onset suggests an immune-mediated or vascular process at the level of the posterior root or dorsal root ganglion.