Planktonic sampling was carried out at Serlui ‘B’ dam, Mizoram, northeast India from July 2016 to April 2017. The present study reported the occurrence of 6 groups of phytoplankton belonging to 27 genera and 16 orders and 4 groups of zooplanktons belonging to 12 genera 7 orders. The phytoplankton group consisted of Cyanophyceae, Bacillariophyceae, Ulvophyceae, Zygnematophyceae, Chlorophyceae and Xanthophyceae. Cyanophyceae were the predominant component of phytoplankton in Serlui ‘B’ dam during all seasons in terms of numerical abundance and account for 64% of the total phytoplankton. The zooplankton groups consisted of Maxillopoda, Tubulinea, Eurotatoria and Branchiopoda. Of these, the class Maxillopoda was the predominant component of zooplankton in Serlui ‘B’ dam during all season in terms of numerical abundance and account for 73% of the total zooplankton encountered from the study site. This study provides preliminary report of planktons of Serlui ‘B’ dam.