This study aims to explore the diversity of aquatic macroinvertebrates in the Nogosari River and study the physicochemical parameters. The research sample was taken using a plot with a purposive random sampling method. Each station is installed 3 plots and each Plot measuring 1m x 1m. Data analysis was carried out by describing and calculating the macroinvertebrate diversity index found. This study found 12 families of macroinvertebrates in the Nogosari River. The macroinvertebrate diversity index was calculated using the Shannon-Wiener Diversity Index (H') calculation (Krebs, 1978). The average diversity of macroinvertebrate species in the Nogosari river is 2.51. This value is in the range of 1.0 < H' < 3.322 or the category of diversity index at the Medium level. This means that the diversity of macroinvertebrates in the Nogosari River has sufficient productivity, and the condition of the ecosystem is quite good. The water quality in the Nogosari River is categorized as moderately polluted. It was calculated based on the Biotic Index Value with an average BMWP-ASPT score of 5.83.