No study has examined the effect of case management on the development of the metabolic syndrome. The authors randomized 450 consenting, asymptomatic men and women to a 6-month cardiovascular case management program or usual care. Participants were reassessed at 1 year for change in a composite measure of five factors that define the metabolic syndrome. Of the cohort (mean age 42 years; 79% male), 46% had at least one metabolic syndrome factor and 4.3% had the metabolic syndrome. At 1 year, there was greater improvement in motivation to change in the case management group (+0.58 vs. +0.06, 10-point scale; p=0.001), lower incidence of the metabolic syndrome (1.5% vs. 4.5%; p=0.12), and lower prevalence (decrease of 0.8% vs. increase of 2.6%; p=0.04). A 6-month case management program focused on cardiovascular risk factors had a modest effect on the prevalence of the metabolic syndrome in this primary prevention screening population after 1 year. Further study is needed to clarify the overall health impact of preventing the metabolic syndrome.