Xeroderma pigmentosum is a genetically heterogeneous disease caused by DNA repair defects resulting in skin cancer and, in some patients, a primary neuronal degeneration which has in all previous reports become symptomatic prior to age 21 years. A 47-year-old xeroderma pigmentosum patient is described who, although neurologically asymptomatic, has sensorineural hearing loss together with clinical signs and electrophysiologic evidence of a developing peripheral neuropathy. This case suggests that defective DNA repair may cause neurodegeneration in adults as well as in children.