The growth of cities in the state of São Paulo has caused major impacts on aquatic ecosystems, as in Tatuí River, which is part of the Sorocaba River basin and MiddleTietê. Studies on its ichthyofauna are relevant to the conservation and monitoring of the river, under the optics of Tatuí river is one of the largest contributor to the pollution of the river Sorocaba. This study aimed to survey the fish fauna of the Tatuí river and relate them to anthropogenic interference which is submitted. Were collected during the dry and rainy seasons of 2010. Considering all the work already done on the Tatuí river were raised 53 species. This worked identified 18species of fish, belonging to 9 families and 2 orders. The most representative family was Characidae, with 5 species followed by the family Loricariidae, with 3 species. The most abundant species was Hypostomus margaritifer, followed by Hypostomus ancistroides. The result corroborates with other studies conducted in Paraná High and Sorocaba River basin. Inverse correlation was obtained between total dissolved solids and diversity. What is explained y the Tatuí river find themselves impacted throughout its length, especially the lack of riparian vegetation, siltation and domestic sewage and industrial.