The Mazama gouazoubira population density was estimated in the Mburucuyá National Park (Corrientes, Argentina). The assessment methods used where: strip transects sampling. Samplings were performed from June 2008 to February 2011, distributed at summer and winter in daytime hours (0600 - 1000 h) and night (1900 - 2200 h) in three habitats: mesophilous forests, "pajonales" (tall grasslands) and yatay palm groves. A number of 186 records were obtained after 344.76 km traveled. The calculated population size was 430 individuals (CI = 324-548), based on available habitat area in the park (62.3 km2), and an estimated average density of 6.9 ± 0.9 brocket deer/km2. Density varied significantly in each area: 11.2 ± 1.4 ind/km2 in mesophilous forest, 3.5 ± 1.1 ind/km2 in pajonales, and 5.5 ± 1.5 ind/km2 in yatay palm groves. Results showed Mazama gouazoubira's higher affinity for mesophilous forests. Population density estimates of this species will allow monitoring and future studies in the northeastern region of Argentina.
