Despite the economic importance of PRRS and its high prevalence in Costa Rica, there are no studies on the bioeconomic impact of the disease in the country or, even, in Central America. Therefore, the objective of this study was to evaluate economic and production parameters of a PRRS-free baseline scenario against three scenarios with low, medium and high PRRS effects for a medium-sized farrow-to-finish pig farm system in Costa Rica. A farm-level stochastic Monte Carlo simulation model was developed to simulate the bioeconomic performance during one-year production cycle of, working under the tropical circumstances prevailing in Costa Rica. The effect of PRRS on farm performance was assessed by scenario analysis, in which a baseline PRRS-free situation was compared against three alternative scenarios that assumed low, medium and high PRRS effects. The PRRS effects were incorporated in the model based on data from local farms, scientific literature and expert opinion. Sensitivity analyses were performed to assess the impact of key input parameters on output variables. Results show that at the animal level, changes between the baseline and the PRRS-high scenario were estimated as: +25 d in age to slaughter, -9.9 pigs to slaughter (per breeding sow/yr), + 6 % annual replacement rate, -255 d in sow productive lifetime, - 6.9 mo in age at culling of sows, and + 24 non- productive days. For a medium size local farm (n=588 sows), a reduction of 5,826 fat pigs to slaughter per farm/yr from baseline compared to PRRS-high scenario was observed. PRRS-induced loss per farm per year was estimated at -US $142,542, US $180,109 and -US $524,719 for PRRS-low, medium and high scenarios, respectively. Revenues/costs ratio changed from 1.12 in the baseline to 0.89 in the PRRS-high scenario. The production cost per kg carcass weight increased from US $2.63 for baseline to US $3.35 in PRRS-high scenario. PRRS-induced loss was estimated at US $77.1 per slaughtered pig/yr and US $892 per breeding sow/yr for PRRS-high scenario. Results from the model reflect current bioeconomic impact of PRRS in local farms in Costa Rica, which can be helpful in the design of better control strategies for this disease