A prospective study of 52 boxers, 20-60 years, 13 of them amateurs and 39 professionals, has been made using magnetic resonance imaging (MRI) at 0.15 T. Twelve of the boxers were still active, while the other 40 had retired after about 10 years of boxing. Multi-slices in two planes without gap were performed using T1 and T2 weighted sequences. The findings were correlated to the number of matches, the number of knock outs, the severity of head trauma, the style of the boxer, and to the clinical findings and the findings at EEG. There was a good correspondence between the presence of lesions and the style of the boxer. The changes noted--mainly atrophic--occurred among those with capacity to 'stand punishment'. MRI offers an opportunity to evaluate the effect of trauma and the information obtained may be used to prevent disabilities among boxers.