This article reports the effect of a worksite cancer control intervention on aspects of the physical and social environment related to dietary and smoking behaviors of employees. Data are from 111 intervention and control worksites that participated in the Working Well Trial. Employee surveys and interviews with key organizational informants assessed environmental and normative changes relevant to nutrition and tobacco use. Results indicated significant effects of the intervention on all nutrition outcomes: access to healthy food, nutritional information at work, and social norms regarding dietary choice. Significant benefits were not found for smoking norms or smoking policies. However, changes occurred in both the control and intervention sites on these variables. This first large analysis of environmental and normative effects of a worksite intervention is consistent with the employee behavior change findings for the trial and serves as a model for future analyses of multilevel worksite health promotion programs.