In this study the composition and diversity of aquatic macroinvertebrates were evaluated in the reservoir of water captation of Batalha river, for treatment and supplying of the city of Bauru. The samples were made in dry (from June to August/2005) and rainy (from December/2005 to February/2006) seasons. We analyzed and identified 840 organisms belonging to 8 taxa (8 taxa in dry season and 4 in rainy season). The system presented low abundance and diversity of macroinvertebrates probably in response to water quality and physical and chemical variations in the characteristics of water associated with the occurrence of rain.
