This study was developed along the main channel of João Leite River, Upper Paraná River Basin, Goiás State. Three stretches with 500m length were predetermined and fish species sampled in each on them. Fish sampling was carried during dry season using a set of nets with different mesh sizes (12, 15, 20, 25, 30, 35, 40 and 50mm between knots) and five traps. The α diversity was verified through ecological descriptors such as species richness, abundance, Shannon-Wiener index and evenness while β diversity by Morisita-Horn index. Species richness and diversity increased towards upstream-downstream as expected by river continuum concept... Keywords: João Leite River; Ichthyofauna; Diversity; Longitudinal Distribution.