The goal of this article is to contribute to a burgeoning comparative literature about nationalization of party competition (political parties and party systems), clarifying its terminology and evaluating three different indices of measurement of this phenomenon and used recently in Latin America. This paper argues that despite the confusion in the terminology, the term nationalization should be understood as homogeneity of electoral support across the territory and that a proper measure of nationalization should take into account four basic elements: party presence across the country, number of subnational units where it is measured, its magnitude and the size of the party. The revision of the literature dedicated to Latin American countries reveals that more case studies of longterm evolution of party systems and explanation of its changes and party-centred variables are necessary.