The nuclear magnetic resonance images obtained in a case of adrenoleukodystrophy are presented. The areas of demyelination are clearly seen. The T 1 values of the affected areas are not specific and coincide with those previously recorded in the lesions of multiple sclerosis or cerebrovascular disease. A diagnosis of adrenoleukodystrophy should be considered in younger male patients presenting with behavioural disturbances, especially when these are associated with abnormalities of vision or gait. There may be no clinical evidence of the associated adrenocortical insufficiency.