A few attempts have been made to analyse whether market potential might also have an impact on urban structures. In this paper we employ parametric and non- parametric techniques to analyse the effect of market potential on the growth of Spanish cities during the period 1860-1960. This period is especially interesting because it is characterized by the advance in the economic integration of the national market together with an intense process of industrialization. Our results show a clear positive influence of market potential on city growth.