So far, Phragmites australis was omitted in exploration of chlorophyll dyes content in grasses. Elimination of this gap was the aim of this research. Works was carried out during growing season in 2013. Object of the research was reed from 8 reservoirs, in different sizes, located in western part of Poland. Plants were overgrown periphery of water basins, along the shoreline, and communities can be classified as Phragmitetum australis. Studies consisted of systematic, during the growing season – monthly, analysis of chlorophyll dyes presence in leaf blades. Obtained results bring significant value in biological characteristics of this species.