Phytoplankton is a primary producer organism in aquatic ecosystem and it supplies oxygen to the waters through photosynthesis process. A research aim to determine types and abundance of phytoplankton in the Sungai Paku Reservoir has been carried out on June-July 2019. Sampling taken at three stations, namely Station 1 (riverine zone), Station 2 (transition zone) and Station 3 (lacustrine z…