A decade ago, in a review of the field Roger Schofield and David Reher observed that ‘the basic demographic parameters of mortality decline are still far from clear’. And in spite of admirable analyses of mortality by authors ranging from Eilert Sundt in 1855 to Julie A. Backer and Michael Drake in the 1960s and Sølvi Sogner and Ståle Dyrvik in the 1970s, this observation also generally applies to Norway. Some of the lack of clarity is due to the limitations of the death data themselves, some to the orientation of researchers. For example, although almost every biography of a Norwegian town has its section on births and deaths, the study of urban mortality as a whole has not attracted much attention, perhaps because the situation seems self-evident. Towns were (and still often are) unhealthier places to live in than the countryside. Referring to the years 1831–1850, Sundt posited the laconic axiom that ‘Dødelighenden i byerne pleier være større end i landdistrikterne.’ From this starting observation, which was of course true at the time, I want to examine urban mortality in Norway in the context of state-wide mortality trends from the mid- nineteenth century to 1920. Ultimately I intend to study mortality on the individual/family level in the western coastal towns of Bergen and Haugesund during this period, using machine-readable nominative sources, censuses, and parish registers. However, to put these intended microhistorical investigations in perspective, I have delved into published statistics on mortality in Norwegian towns in general and in Kristiania (now Oslo) and Bergen in particular. These data are plentiful and readily available but they are not always in a form suitable for systematic analysis over a long term; they must be collated, organized, and to some extent massaged. In the investigative tradition of exploratory data analysis I am looking for patterns in the data and meanings in the patterns. A number of questions guide the description and analysis. How big was the urban–rural differential and how did it change over time? What were its components; or rather, who paid the ‘urban penalty’? The answers show that urban mortality was an important factor in the mortality transition in late-nineteenth-century Norway.