Familial hypercholesterolemia (FH) has a prevalence of 1 in 500 in Western society and predisposes for premature cardiovascular disease. Lipid-lowering treatment of affected individuals is widely advocated. Maximum health benefit can be obtained in FH if treatment is started as early as possible, as the World Health Organization has recently recommended. In 1994 we initiated an active case-finding program for individuals with FH, based on family investigation and DNA-testing. In an initial pilot study we established that active family screening supported by DNA diagnostics resulted in the identification of substantial numbers of FH heterozygotes and determined that diagnosis by DNA analysis was superior to conventional cholesterol measurement. Since its initiation, the program has led to the identification of more than 6000 individuals with FH, of whom the greatest part was not adequately treated at the time of identification. Our findings indicate not only that this case-finding approach is effective in identifying FH patients who otherwise would not have been identified but also that the vast majority of these patients seek treatment and are successfully started on cholesterol-lowering therapy to reduce their risk of premature cardiovascular disease. Here we describe an effective model to identify and bring under treatment large numbers of individuals affected by FH.