Familial hypercholesterolemia (FH) is associated with pronounced atherosclerosis leading to premature cardiovascular disease and untimely death. Despite the availability of effective preventative drug treatments, many affected individuals remain undiagnosed and untreated until they become symptomatic with cardiovascular disease. To assess the cost-effectiveness of systematic genetic screening of family members of persons diagnosed with FH, an analysis was conducted using data from a nationwide screening program for the identification of individuals with FH, instituted in The Netherlands in 1994, and from other sources. There was DNA testing of families with a known genetic defect to identify new cases of FH in the presymptomatic stage of the disease. After identification, most newly identified patients were started on cholesterol-lowering statin treatment. On average, new cases diagnosed by the screening program gained 3.3 years of life each. Twenty-six myocardial infarctions would be avoided for every 100 persons treated with statins between the ages of 18 and 60 years. The average total lifetime incremental costs, over all age ranges and both sexes, including costs for screening and testing, lifetime drug treatment, and treatment of cardiovascular events, was US dollars 7500 per new case identified. Cost per life-year gained was US dollars 8700. Therefore, systematic genetic screening of family members of persons diagnosed with FH is cost-effective in The Netherlands and should be considered for other settings.