Two siblings with Cockayne syndrome are reported who had most of the stigmata characteristic of the syndrome as it was initially described in 1936. Unusual findings are emphasized, such as the early onset of cataracts and the early detection of peripheral neuropathy. The previously reported autopsy abnormalities in this condition are correlated with the present magnetic resonance imaging findings of mild ventricular enlargement and delay in myelination of the cerebrum and cerebellum. Properly myelinated structures included the basal ganglia, thalamus, internal capsule, splenium, and genu of the corpus callosum.