Among 8735 autopsies performed during a 5-year period at Ullevål Hospital in Oslo there were 70 cases of Wernicke's encephalopathy (0.8%) and 152 cases of alcoholic cerebellar atrophy (1.7%). Cerebellar atrophy was found in 26.8% of all examined alcoholics. Twenty-two of the cases with Wernicke's encephalopathy were active (acute and subacute) and 48 were inactive (chronic). Examination of the clinical records showed that stupor and coma were the dominating symptoms in active cases. A pure Korsakoff's psychosis with a selective memory defect was present in about one-third of the cases with inactive encephalopathy while the remaining had more or less pronounced global dementia ("alcoholic dementia"). It is suggested that inactive Wernicke's encephalopathy is the main underlying lesion both in Korsakoff's psychosis and "alcoholic dementia" but that additional lesions are present in the latter group. The brain weight in 545 male alcoholics was compared with that of 586 controls. Cases with non-alcoholic brain lesions were excluded from both groups. In alcoholics the brain weight was significantly lower than in controls in all age groups below 70 years. The mean weight difference was 31 g. The study thus confirmed the existence of a generalized alcoholic brain atrophy.