Descriptive statistics were collected from a sample of randomly selected employees at each of the five worksites. Questionnaires were administered at the first worksite in 1991, at the second and third worksites in 1992, and at the fourth and fifth worksites in 1993. The data collection instrument was approximately 30 pages long, and most people took 30 to 45 minutes to answer the questions. Confidentiality protection was an important survey condition. Workers in the sample were predominantly white, well-educated, and married. Compared to national averages, workers at the five sites tended to have substance use profiles similar to or slightly lower than estimates from large national surveys. About 15 percent of workers were heavy cigarette smokers. Most workers consumed some alcohol during the past year, but fewer than 11 percent were daily drinkers and about 6 percent were heavy drinkers. Illicit drug use during the past year was reported by about 5 percent of workers. In contrast, about 17 percent of workers reported prescription drug misuse. The only workplace consequence reported by more than 10 percent of substance users was poor performance. It was determined that survey findings may help employers identify the extent of substance abuse problems in the workplace and target specific areas for possible intervention. 8 references and 5 tables