Urbanization is the process of a city’s growth, and the construction of urban infrastructure changes the natural environment. The goal of this thesis is to investigate: (i) the taxonomical composition and abundance of macrozoobenthos, (ii) the difference in the taxonomic composition and abundance of macrozoobenthos during two seasons (spring/autumn), (iii) the type and mass of microplastics in sediment samples collected during spring and autumn 2021 at two sites (V1, V2) located along the Vrapčak stream which flows through the city of Zagreb.. By sampling every two to three weeks 24 samples were collected in spring and 18 in autumn.. Apart from extracting and identifying macrozoobenthos, the phase analysis, analysis of microplastics, the content of the carbonate component, and the analysis of physicochemical parameters in the water samples were also analyzed. The abundance of macrozoobenthos was higher at the site V1 during the entire research periodand in spring. In the spring, significantly more Diptera and Ephemeroptera individuals were observed, whereas in the autumn, there was significantly more Isopoda individuals, which indicates the seasonal life cycles of these macrozoobenthos taxa. The most abundant taxa in the samples were Chironomidae and Oligochaeta. Out of the 76 particles recorded by the spectrophotometer, 16 of them showed a good match with certain plastic polymers found in literature. Physicochemical water parameters between the sites did not show significant differences, but most of the measured parameters differed significantly between the two investigated seasons.