The importance of patterns of urbanization and migration in Colombia for the design of appropriate policies for regional, urban, and intermediate city development were explored. Discussion reviews the growth of the 19 major municipios over the 1918-64 period, the date of the most recent available census, and focuses on the interaction between a program of intermediate city development and the process and patterns of migration. When these cities are ranked by size from largest to smallest, a high degree of stability of rankings over the 50 year period is evident. This stability supports the hypothesis that an articulated hierarchy and system of cities has developed. That development in turns owes much to the flow of migrants into the cities. Largely it results from intensive migration into the 4 largest cities, their share of the total population of the 19 urban municipos increased from 46% in 1918 to 62% in 1964. Migration thus made it possible for the 4 large cities to grow much faster than the intermediate cities for migrants were choosing the largest urban areas as a place to which to migrate. The "pull" of the largest cities was obviously considerably greater than that of the small cities. In the late 1960s the government began to consider whether some plan was needed to stem the tide to the largest cities and to redirect it to intermediate centers. The plan of Dr. Lauchlin Currie, a radical departure from extant policy when presented to the Lleras Camargo government at the end of the 1950s, was to hasten the process of cityward migration, for several years accompanied by a massive expansion of urban housing and economic development. The objective of moving people to the capital was achieved but the complementary structural changes in the urban economy have not been. As Currie himself recognized some years ago, there has arisen a crisis for Bogota in the provision of necessary public services. The average quality of migrants to Bogota is lower than the quality of migrants going to other major cities in Colombia. If successful, the program of intermediate city development will divert interurban, high quality migrants from Bogota to other cities. Yet, the problem of migrants in Bogota's inner city will not be affected, whatever the benefits to the secondary cities. A parallel strategy of rural and small town development is necessary to supplement intermediate city development. Such a strategy would prove particularly important to the future population distribution of Cundinamarca and Boyaca, which constitute the immediate hinterland of Bogota. Promotion of selected small towns in those departments should take advantage of the external economies of some proximity to the metropolis, but there should be sufficient distance to allow the continuation of greenbelt areas and to limit congestion. Small town development itself might assist in revitalizing a countryside sapped by cityward migration and the massive movement to better opportunities in neighboring Venezuela.