The Paraguayan party system, centered on two 132-year-old parties seemingly poised to remain alive and well for years to come, constitutes an anomaly in Latin America. This chapter discusses the evolution of the Paraguayan traditional parties highlighting their changes and continuities in two different historical settings: the nondemocratic period, which includes a semi-competitive (1870–1940) and a dictatorial subperiod (1954–89) and the post-1989 democratic period. The findings point to three distinctive features of the Paraguayan party system: the ability of the traditional parties to plant deep roots into the country’s social structure facilitated by historic and institutional factors; the capacity of the parties to aggregate in a clientelist mode the interests of a population that lacks strong collective actors, made possible by a socioeconomic societal matrix; and the versatility with which parties have coordinated interests, both in semi-democratic as well as in democratic settings, which includes electoral mobilization but also civilian recruitment for armed uprisings. Finally, the chapter discusses possible future trends in light of the growing influence of illegal financing and recent changes to the rules governing elections mandating the system of “open lists.”