The pace of population growth and unplanned urbanization the pace of population growth in the countries of Latin America was determined and still determine multiple problems. A country keep its population benefited due to its evolution, requires a greater proportion of investment that will accelerate economic development and even greater government investment in housing, health, education, transport and infrastructure in general. But not only that, will require four reforms such as: agrarian reform, industrial reform, tax reform and education reform. Credit: REBNY-2011. The Economic Commission for Latin America and the Caribbean (ECLAC) estimated that in order to maintain the intense pace of economic growth required by the population increase, the countries of Latin America already should have increased, for the year of 1975, its industrial production by 400 percent and its agricultural production by 120%, therefore needed to give employment to a force labour had already grown at 35 million people, of whom 86% demanded employment in Industrial Park close to urban areas and 14 per cent in rural areas. Even investments in urban areas should be heavily expanded, in order to provide housing, education and health and also related services and infrastructure services in general (Harris, 1975, a.p.assanelli-66). As we know these forecasts could not become public policies by lack of resources and lack of timely decisions to perform the four reforms that we pointed out previously. The ever-increasing housing demand and little supply, opened a gap with the result of the formation of marginal slums (favelas, proletarian colonies, ranches, mushrooms) that were mixed in the same urban spaces occupied by the middle class and the wealthy. The movement of groups of low income toward the periphery was and is most dramatic in those cities that have had a high rate of population increase, but without a proper industrialization, without improvements on agricultural production and without implementing other necessary reforms. Even the density of people per hectare in those marginal areas they may be almost equal to the density in the urban centre of the metropolis.