[Excerpt] This paper builds upon earlier work of mine which explored the determinants of population migration in Colombia. As before, the basic proposition is that areas' economic opportunities play a central role in determining the spatial allocation of the population. My earlier paper used published data from the 1973 Colombian Census of Population to establish that the rates of net lifetime migration into Colombia's 23 provinces (or, as they are known in Colombia, "departments") are associated with those areas' labor market conditions. The present paper uses unpublished data for 12 zones (six regions, rural and urban segments of each) to analyze the causes of place-to-place migration flows (lifetime and recent) for the population as a whole and for eight specific demographic groups (four educational categories and the two sexes). Several hypotheses are formulated and tested. The results give strong support to the economic model of migration, overall and in explaining differences in migration behavior among demographic groups. For Colombia this is particularly useful since some past work has been interpreted to the contrary.