Cranial CT in a case of Sjögren-Larsson syndrome (SLS) showed a striking loss of attenuation of supratentorial white matter. This is in accordance with the myelin loss found at microscopic brain examination of patients with SLS, but not with the only report of five patients examined by cranial CT. The considerable myelin loss may be detected only by more recent generations of CT scanners and seems to be stationary during lifetime.