Historians and demographers have long debated the existence, causes, and consequences of historical differences between urban and rural mortality levels. In Europe it has been usual to observe excess mortality in cities compared to the countryside, but in East Asia, by contrast, it has been found that urban areas had relatively favorable mortality environments. The debate continues because a number of pertinent questions remain to be resolved. For example, the way in which mortality is measured may influence the apparent extent of the differential, as may the way in which“urban” and“rural” are defined. Cultural factors need to be taken into account, including the practices of childrearing and the conventions surrounding baptism. Examples drawn from Japan, China, England, and France illustrate the issues involved in comparative analysis, while the urban-rural mortality continuum is examined for nineteenth-century England and Wales using log-normal distributions.