Coronary artery disease is a complex and multifactorial pathology. Although the environmental component of coronary artery disease has been thoroughly investigated and is hence well known, knowledge about the genetic factors implicated in this disease is still scarce. Technological advances and the fact that the Human Genome Project has almost been completed allow the application of approaches that were not feasible few years ago to the genetic investigation of complex diseases. The aim of the PROCARDIS study is to identify new susceptibility genes of precocious coronary artery disease, through a genome-wide screen applying statistical methods of linkage analysis followed by a family-based association study. The originality of PROCARDIS lies in the fact that it is an international multicenter study. This allows recruitment of a very large number of individuals so that the population size, considered up to now unachievable, is adequate for the aims of the study.