Along its entire course, the Sava River in Croatia is exposed to different anthropogenic stressors. Partition channel construction, embankment construction, fortifying the coast, introduction of foreign species and commercial and recreational fishing have an impact on native species populations. The aim of this research was to compare the ichthyocenoses of different parts of the Sava River, to assess the state of stress in the investigated locations and analyze changes in the composition of the ichthyocenoses for individual locations. Regular systematic research of the ichthyofauna of the Sava River is necessary to assess the impact of anthropogenic stressors in order to preserve the native species of freshwater fish. Data on ichthyofauna and fish biodiversity were collected during regular monitoring of Sava River for each year, but more thorough trend analysis of changes in ichthyocenoses over a longer period, as well as assessment of stress in the communities of the researched locations was necessary. Data on ichthyofauna were collected as part of regular monitoring of the Sava River over the period of 2018 to 2021. at the locations of Medsave, Lijevi Dubrovčak, Jasenovac, Gornji Varoš and Slavonski Brod. Samples from each location show the abundance and biomass of fish on a 100 m section. The fishes were collected by electrofishing moreover, basic physical and chemical parameters of the water were also observed at each location. Differences between the ichthyocenoses of different parts of the stream were analyzed using ANOSIM (analysis of similarities) test and the species that contributed more to the differences between locations and individual years for each location were determined using SIMPER (similarities percentage) analysis. Changes in the stress state of communities were evaluated by calculating the ABC (abundance biomass comparison) index for each location and year of research. Kruskal-Wallis analysis tested differences in the state of stress and biodiversity between locations. During the research, 26 species of fish were found, all of which were known to inhabit the Sava River. Location Medsave differed the most from the other locations in terms of species composition. Number of species on the locations varied randomly from year to year, there was no constant trend. No significant difference was identified between the locations in the biodiversity index and the state of stress.