The article presents a floristic study carried out in 2015–2020 in the northern part of the urban district of Zaraysk, Moscow region (the right-bank part of the lower course of the Osetr River, the vicinity of Spas-Doschatyvillage). Taking into account herbarium collections, a floristic list of 278 plant species belonging to 68 families was compiled. A comparative analysis of modern data with floristic data published in 1953 for this region is carried out. It was revealed that the main reasons for changes in plant communities were work on artificial afforestation, the cessation of grazing by domestic animals, a decrease in the area of hayfields and an increase in the area occupied by arable land. As a result of anthropogenic factors associated with the restructuring in agricultural activity and animal husbandry, a floristic transformation took place in the 21st century, which affected the structure and composition of forest and meadow communities. There are 11 invasive species in the study area: Amaranthus retroflexus L., Erigeron canadensis L., Matricaria disco-idea DC., as well as later appeared Heracleum sosnowskyi Manden., Acer negundo L., Bidens frondosa L., Echinocystis lobata Torr. et Gray, Impatiens parviflora DC., Galin-soga quadriradiata Riiz et Pav., Populus alba L., and Reynoutria × bohemica Chrtek et Chrtkova. These species have a negative effect on the components of the native flora, subjecting natural landscapes to significant transformation. It was revealed that 8 rare and vulnerable species need constant monitoring: Juniperus communis L., Pyrus communis L., Salvia pratensis L., Campanula bononiensis L., C. latifolia L., C. trachelium L., C. persicifolia L. and Convallaria majalis L.