An epidemiologic transition to high prevalence of such diseases as diabetes and coronary heart disease accompanies the process of modernization/industrialization. I suggest that an equally clearly defined epidemiologic transition characterizes malaligned and discrepant dental occlusal relations in western societies, and others undergoing urbanization, and that the rapidity of the transition is proportional to the rapidity of urbanizational change. This phenomenon rather throws the weight of suspicion toward environmental, not genetic, etiologic factors. The dental occlusal epidemiologic transition provides a model for developing further research into causes of malocclusion.