The purpose of this study was to evaluate the short-term effects of a low-intensity work-site heart disease risk reduction program using a matched pair design with work site as the unit of analysis. Twenty-six heterogeneous work sites with between 125 and 750 employees were matched on key organization characteristics and then randomly assigned to early or delayed intervention conditions. Early intervention consisted of an 18-month multifaceted program that featured an employee steering committee and a menu approach to conducting key intervention activities tailored to each site. Cross-sectional and cohort analyses produced consistent results. At the conclusion of the intervention, early and delayed intervention conditions did not differ on changes in smoking rates, dietary intake, or cholesterol levels. There was considerable variability in outcomes among work sites within each condition. Despite documented implementation of key intervention activities and organization-level changes in terms of perceived support for health promotion, this intervention did not produce short-term improvements beyond secular trends observed in control work sites. Research is needed to understand determinants of variability between work sites.