One hundred ten consecutive alcoholics who voluntarily entered a detoxification center were studied to determine their ability to perform certain designated functions (a) while under the influence of alcohol at admission and (b) four days later, after they had undergone detoxification. Their blood alcohol concentrations (BACs) within an hour of admission were determined by using the DuPont Automated Clinical Analyzer (ACA), following standard procedures. The results of the tests performed by these subjects were then studied to ascertain the level of psychomotor impairment in alcoholics at elevated BACs. The results were broken down by age, sex, race, and BAC. The findings indicate that alcoholics develop an increased tolerance to alcohol at BACs, which are extremely high, including levels generally considered to be potentially fatal.