A Connecticut insurance company adopted a policy prohibiting smoking in all work areas. Three months later, the authors assessed smoking behavior changes and attitudes of a sample of 1,210 employees, 56.6 percent of the total. The survey showed that the policy of no smoking in the work areas did not markedly affect smoking cessation, that it reduced cigarette consumption for those who continued to smoke, that those who previously smoked most were most likely to reduce consumption, and that despite negative feelings about the policy by smokers, only 29 percent of smokers and 4 percent of nonsmokers wanted a worksite smoking policy eliminated. During the 1-year prepolicy period, smoking prevalence decreased from 25.2 percent to 23.6 percent of the sample. During the 3-month postpolicy period, smoking prevalence decreased to 22.0 percent. During the prepolicy period, consumption did not change significantly (from 0.99 to 0.95 packs per day) and few smokers increased (11 percent) or decreased (13 percent) consumption. During the postpolicy period, consumption decreased by 32 percent to 0.67 packs per day, and 12 times as many smokers decreased (44 percent) as increased (3.5 percent) consumption. Of those who smoked at least two packs per day, 93 percent smoked less after the policy. Among nonsmokers, 70 percent thought the policy had a positive overall effect on the work environment, compared with 19 percent of smokers.