As many as 65-70 percent of alcohol abusers are estimated to be employed, and 31 percent of 800 large U.S. companies reported employee drug abuse to be a problem in 1974. Four environmental factors influence drinking habits separately or in combination: availability, social pressure to drink, the high degree of mobility which separates workers from the stabilizing influence of home, and relative freedom from supervision. The major effects of alcohol and drug abuse in the workplace are inefficiency, coverup and increased turnover rates, absenteeism, and accidents. Preventive measures should include reduction of the availability of drugs and alcohol at the workplace (primary prevention), health promotion and education (secondary prevention), and treatment services (tertiary prevention). Employee Assistance Programs in a number of countries have been effective in identifying abusers in the workplace and referring them to treatment services. Legislation can influence the attitude and approach of management towards employee substance abuse. Programs should be evaluated to determine their impact on employee social adjustment, employment adjustment, and job efficiency. 40 notes.