Inez Egerbladh holds a PhD. in human geography and is a researcher at the Demographic Data Base, Umeå University, Sweden.ABSTRACT: The long-term development of the households of landed peasants was investigated longitudinally in one village, and cross-sectionally in several parishes in northern coastal Sweden. The results showed a dominance of complex family households in a stem family system during the 1700s and development toward simpler family households in the 1800s. Demographic, economic, ecological, geographic, and, to some degree, cultural factors and their changes over time were taken into consideration in an explanation of this transition.The hypothesis that nuclear families constituted the basic preindustrial household structure in most parts of western and northern Europe, excluding Finland, has generated much research on household structures during the last decades (Laslett