This chapter examines existing activities reported in the literature in the areas of smoking, nutrition, and screening; explores the prominent theories of behavior change that have guided some of these activities; and presents a model for worksite cancer prevention programs that is currently being tested in a large trial. A major theme of this chapter is the need for simultaneous changes in individual behaviors and the worksite environment. For each factor (smoking, nutrition, and screening) the discussion is divided into interventions for individuals and those for the environment or organization.