This paper focuses on the congruence between party positions and voter preferences directly after the “third wave” of democratization in Latin America, and on its historical origins. Latin America displays a wide variation in the degree to which parties are anchored in society and reflect specific social groups. I argue that party systems that experienced ideological polarization in the early 20th century were set on a programmatic track and today are likely to exhibit high levels of congruence in the representation of their voters’ interests. In other contexts, where elites relied heavily on clientelistic resources to de-mobilize the citizenry when the suffrage was expanded in the first half of the 20th century, programmatic representation is likely to remain weak until the 1990s. These hypotheses are verified by combining the PELA-surveys of Latin American legislators with mass-level survey data. The first task is to discuss how congruence between voter preferences and party positions should be measured, which involves not only a number of methodological and conceptual issues, but also questions ultimately rooted in differing normative conceptions of representation. I then move on to assessing empirically what constitutes the relevant dimensions of conflict in seven Latin American countries, and measure the quality of representation along these dimensions. The results not only reveal important contrasts in the congruence of representation across the seven countries studied, but also that these differences can be explained rather well by historical patterns of party system formation.