There is little information on the long-term consequences for employees when no-smoking policies are established in the workplace. Our study was designed to assess changes in employee health and smoking behavior. Of the original 60 subjects, 40 employees (18 smokers, 22 nonsmokers) completed this study, which was conducted in a major medical institution. Nonsmokers were recruited as part of the study to determine whether they showed evidence of workplace carbon monoxide associated with passive smoke, potentially inhaled at the work site. Baseline measurements of smoking frequency, carbon monoxide, and weight were obtained during the month preceding the smoking restrictions and at 6 and 18 months afterward. Smokers made significant reductions in daily smoking during the first 6 months but gradually returned to prepolicy levels over the following year. Smokers, in particular, showed increases in weight. Smokers gained 4.93 lb after 18 months, whereas nonsmokers gained 2.25 lb in the same period. Nonsmoker employees showed no evidence of workplace carbon monoxide exposure associated with passive smoke. We discuss the implications of the findings for no-smoking policies in the workplace.