AbstractCity size plays an important role in the context of growing urbanization in developing countries, such as India. In the backdrop of this fact certain questions are pertinent: whether economic activities are concentrated in a few large cities; which economic factors determine the size of large cities; whether it is possible to trace different groups among the large cities, and whether the relationship pertaining to city size, migration, and poverty is discernible are some of the research issues which are analyzed in this paper by considering 47 million-plus cities in India. The estimated Pareto distribution suggests that within the group of large million-plus cities, production is not so diversified, though the extreme form of concentration such as primacy or rank size rule does not hold either. In fact, three broad groups are evident, as brought out by the results of the cluster analysis. Both OLS and Tobit regression results indicate that the wage rate, amount of municipal solid waste generation, and the number of salaried employed persons are positively associated with city population while the number of registered motor vehicles has a negative effect on it. However, the infrastructure index calculated through factor analysis does not show any significant effect on the city size. Based on the results of factor analysis, increased migration and reduced poverty are seen to be associated with city size. Finally, we bring out the important policy suggestions for sustainable urban development.