Starting from the 1980s, institutions of direct democracy were introduced into most Latin American constitutions. To date, the practical application of these institutions remains almost exclusively restricted to the subtype of government plebiscites while the use of citizen initiated instruments remains scarce. To explain the region's low frequency of use of citizen initiated instruments of direct democracy this explorative study proceeds in three sections. The first recapitulates regulatory legislation on, and practical experience with direct democracy in Latin America. The second proposes and applies an index for the comparative measurement of legal obstacles provided by institutional frameworks and goes on to discuss further explanatory propositions on factors that may interact with these legal obstacles to obstruct direct democratic citizen participation. Finally, these hypotheses are tested through an interview-based study with actors involved in the recent practical experience with direct democracy in Costa Rica. The study concludes that the institutional design of citizen initiated instruments of direct democracy alone does not suffice to explain the frequency of their practical application. Rather than this, application frequency appears to be a function of the combined interactive effects of legal institutional factors with sociological and political party factors such as strategic action preferences and party elites' attitudes.