The structure and distribution of phytobenthic communities are presented and the effect of the depth gradient on the development dynamics of the bottom algae in the Goczałkowice Reservoir described. The investigations revealed the existence of qualitative and quantitative differences in the algal communities between the littoral and the central part of the reservoir. In the backwater part an intermediate type of community of riverine-lake character has developed. Along the depth gradient changes were observed in the algal communities. Active phytobenthos developed in the photic zone to a depth of about 2 m.