In this work we analyse the statistical distribution of the city size for the Spanish case during the period 1900-1999. To that end, we begin with the econometric specification of Pareto’s distribution and Zipf’s law, with the latter being a particular case of the former. The introduction of nonlinear terms in the relevant equations also allows us to explore the existence of nonparetian behaviour in the distribution. The main result, one that is obtained from different empirical approaches is clear, namely that the Spanish urban structure experienced a deep change in its evolution around the mid-1970’s. Coinciding with the onset of democracy, distribution becomes more egalitarian and a negative correlation appears between movements in the ranking of cities and their size.

Key words: Spanish urban structure, Pareto's distribution, Zipf's law.
JEL classification: R11, R12.