The ichthyofauna herein presented was collected in streams, lake, and swamps from the Parque Estadual de Itapeva, Rio Mampituba basin. The protected area is located in the northernmost part of the coastal plain of Rio Grande do Sul state. Samplings resulted in 26 species, in 20 genera, 15 families, and six orders. Two species are listed as threatened and one near threatened in Rio Grande do Sul. This study represents the first fish survey in the protected area, Atlantic Forest biome.