Demographic trends suggest that up to 5000 new cities of half a million in population each may be required between 1975 and 2000. In order to examine the implications of this for demands on resources, a detailed assessment has been made of the patterns of flow and the end-use of energy and of some selected materials in the city-state of Hong Kong. This assessment is used as a basis for extrapolating the future resource requirements of other urban development along similar lines. The calculations indicate that the capital and recurrent energy costs of the predicted urbanization would amount to more than five times the 1973 world consumption of energy.