The study included mesotrophic Lake Piaseczno, located in the Łęczna-Włodawa Lake District. The aim of the study was to evaluate changes of water vegetation of a mesotrophic lake subjected to strong recreational pressure. Specifically we sought to better understand which natu-ral landscapes and anthropogenic developments stimulate or impede macrophyte development and spread. The study was conducted in July in 1997, 2007 and 2017 in three transects: the peat-bog (northern part of the lake), the recreational area (southeast part) and the agricultural area (east). The phytolittoral zone was analyzed from the shoreline to the maximum range of macrophytes occurrence. The study included all groups of macrophytes. Macrophytes in the mesotrophic Lake Piaseczno are still subjected to successive changes. Clearly increased diversity among emergent macrophytes, while a group of submerged macrophytes decreased. The largest changes among analyzed groups of macrophytes occurred in recreational and agricultural transects. Macrophytes have increased the range of occurrence, which may be due to hydrological changes associated with raising the overall water level, thus with increasing the area of the littoral. Impoverishment of diversity among elodeids shows the processes associated with the increase in Lake trophy.