Thirty-six male alcoholics (13 with Korsakoff's syndrome) and 24 controls performed visual and auditory delayed-response tasks sensitive to prefrontal cortical damage in nonhuman primates. Korsakoff patients were consistently impaired compared with other subjects. Impairments by Korsakoff patients were evident when demands were placed on visual processing time (brief stimulus durations), and the deficits became exaggerated with increased demands on short-term memory. Under the most difficult experimental conditions, controls and non-Korsakoff alcoholics who were over 50 years old performed somewhat worse compared with younger groups 27 - 49 years old. Age-linked deficits were mild compared with Korsakoffs' deficits, and age - group differences disappeared with easier task demands. The results implicate cortical pathology in alcoholism and normal chronological aging and suggest that prefrontal damage accompanies alcoholic Kofsakoff's syndrome.