Nineteenth-and early-twentieth-century industrialization provoked quantitative and qualitative changes in traditional European migratory patterns. Most of the economic and social history literature concerning the study of European internal migration during the industrializing period has emphasized permanent migration. This article shows, however, that temporary internal migration was common not only in preindustrial societies but in industrializing ones too. The article also examines the causes and the consequences of the persistence of temporary internal migrations in Spain from the mid-nineteenth century to the period leading up to the outbreak of the Spanish civil war . Aggregate data sources are used in depth for this purpose. The information derived from aggregate sources is supplemented by reference to secondary sources, mainly comprising local and regional studies.Nineteenth-and early-twentieth-century industrialization provoked quantitative and qualitative changes in traditional European migratory patterns. On the one hand, the first globalization generated mass emigration (Hatton and Williamson 1998;Massey et al. 1998;Hoerder 2002). On the other hand, and taking into account the problems related to the definition and measurement of internal migrants, it has been argued that the phenomena of structural change, industrialization, and urban growth led to an increase in internal migrations (e.g., Baines 1994a; Bade 2003). As the nineteenth century advanced, moreover, many internal migrations tended to become more permanent in nature. Besides this, migrants increasingly moved over medium or