Many activities in the inundation of PLTA Koto Panjang Recervoir Batu Bersurat Village contributed organic matter that affect nitrate and phosphate concentration in waters and increasing the abundance of phytoplankton. A research aim to know the relationship between nitrate and phosphate with phytoplankton abundance in the inundation of PLTA Koto Panjang and it was conducted in June-July 2019…