A study was conducted to evaluate the costs and cost effectiveness of behavioral interventions designed to reduce high serum cholesterol levels in a manufacturing population. A sample of 3202 employees participating in a screening was separated into four intervention groups and a control group. All four intervention groups received an educational program of varying length (1 or 3 months). Two of these groups also received incentives. A second screening was conducted after the interventions to determine effectiveness. The 1-month educational intervention with incentive and the 3-month educational intervention had the lowest costs per participant ($46.28 and $53.09, respectively) and costs per borderline high or high risk participant reducing cholesterol greater than 10% ($285.89 and $351.56) and the greatest effectiveness per dollar spent (0.60 and 0.62). The cost-effectiveness analyses were affected by the impact of the intervention and participation rate. Sensitivity analyses showed that increasing participation had a greater impact on the less cost-effective interventions.