Epidemiology, the study of the distribution and determinants of disease, can help with the understanding and management of stone disease in several ways. First, epidemiologic studies can quantify patterns and the burden of disease. Second, large epiderniologic studies can identify risk factors that may provide insight into pathophysiologic processes related to stone formation. Third, these types of studies offer a means to examine interactions among factors, such as those related to diet or the gene environment. Because nephrolithiasis is a complex disease, an understanding of the epidemiology, particularly the interactions among different factors, may help lead to approaches that reduce the risk of stone formation.