EAP's are worksite-based programs designed to help identify and facilitate the resolution of behavioral, health, and productivity problems that may adversely affect employees' well- being or job performance. The focus is wide-ranging, covering alcohol and other drug abuse; physical and emotional health; and marital, family, financial, legal, and other personal concerns that may affect employees. The numerous studies examined consistently show the cost-effectiveness of EAP's. This analysis also considered the effectiveness of EAP's in relation to individuals with behaviors prodromal to alcoholism and other drug addiction. The authors also observed the preventive contributions of EAP's through workplace education, skills development, and policy and environmental changes. This report concludes that EAP's are important components of comprehensive worksite alcohol and drug abuse prevention programs. Their effectiveness is shown in reducing chronic heavy drinking as the focus of socializing and recreation and in providing increased social support and respect for the recovering alcoholic and other drug-dependent coworkers. Stemming indirectly from the EAP's presence and impact, employers, employees, and the family and community at large can become more thoughtful, reasonable, and careful about the use and abuse of alcohol and other drugs. 46 references