Worksites are a key channel for delivery of interventions designed to reduce chronic disease among adult populations. Although some evaluations of worksite physical-activity interventions have been conducted, to date very few randomized trials of worksite health promotion have included the goal of increasing physical-activity levels as part of a comprehensive multiple risk factor approach to worksite health promotion. This article presents the results regarding behavior change found among the cohort of 2055 individuals who completed three health-behavior assessments as part of their worksites' participation in The Working Healthy Project (WHP), a multiple risk factor intervention implemented in 26 manufacturing worksites. In this study, a randomized matched-pair design was used. Fifty-one percent (n = 2,761) of the employees who completed the baseline assessment also completed the interim survey. Eighty-three percent of those who completed the interim assessment also completed the final survey. The WHP intervention targeted smoking, nutrition, and physical activity. At baseline, 38% of the sample reported engaging in regular exercise, and subjects reported consuming an average of 2.7 servings of fruits and vegetables per day, 7.9 grams of fiber per 1000 kilocalories, and 35.4% calories from fat per day; 28% of the sample were smokers. By the time of both the interim (intervention midpoint) and final (end of intervention) assessments, participants in the intervention condition had significantly increased their exercise behavior, compared with the control condition. There was also increased consumption of fruits and vegetables and fiber in the intervention condition by the time of the final assessment, compared with the control condition. No differences by condition were found with regard to percentage of calories from fat consumed or smoking cessation. These results suggest that among a cohort of participants in a worksite health promotion study, there were significant health behavior changes across two risk factors over time. These data suggest that further investigation of multiple risk factor worksite health promotion is warranted, particularly with a focus on ways to increase participation in these programs and to diffuse intervention effects throughout the entire workforce.