The chronic neurological sequelae of boxing are well described, but there have been few neuropathological studies of boxers dying early in their career. We report the case of a 23-year-old boxer, whose brain showed neurofibrillary tangles in all neocortical areas, but remarkable sparing of medial temporal lobe structures. These tangles, assumed to be the result of repetitive head injury, were the only detectable abnormality: none of the other changes previously described in the brains of retired boxers were seen. The distribution and features of the neuropathological findings in this case suggest that the mechanism of tangle formation induced by repetitive head trauma may be different from that in Alzheimer's disease.