Periphyton is a sessile microscopic organism that attached on immersed substrates. A research aims to determine the type and abundance of periphyton on glass substrate has been carried out in April-May 2018 in the Bandar Kayangan Lembah Sari Reservoir. There were four sampling stations, namely station 1 (in the inlet from the Ambang River), station 2 (in the inlet from the Merbau River), statio…