Comparison of the United Nations’ earliest and most recent projections to the year 2000 suggests that urban and city growth in developing regions has occurred much more slowly than was anticipated as recently as 1980. A modified “urban population explosion” in developing countries since the 1970s conforms to explanatory models of urban growth developed by economists around 1980. Trends in productivity and terms of trade, in particular, have been highly favorable to agriculture as compared to manufacturing, presumably slowing migration to urban centers. Increases in national population growth rates have produced less than commensurate increases in rates of city growth, further supporting an economic and migration-related explanation for unexpectedly slow recent urban growth. Despite the efforts of the United Nations to maintain reliable statistics on urban and city populations, urban population projections should be interpreted with caution because of inadequacies of the data on which they are based. Moreover, current projections that virtually all world population growth in the future will occur in urban areas of developing countries may be misconstrued, if the forces that have retarded urban growth in recent years persist.