During the systemic investigations on the desmid biodiversity of Manmecho (Mamencho) lake, Sikkim, Eastern Himalaya, authors recorded 12 taxa belonging to the 5 genera viz. Closterium Nitzsch (5), Cosmarium Corda (4), Netrium Naegeli (1), Penium De Brébisson (1) and Hyalotheca Ehrenberg (1). The following 5 taxa have been recorded as new to Indian flora: Closterium arcuarium Hughes var. arcuarium, Cosmarium impressulum Elfving var. suborthogonum Taft f. suborthogonum, Cosmarium montrealense Croasdale, Cosmarium minimum West et GS West var. subrotundum and Netrium interruptum (Brébisson) Lütkemu ller var. minor (Borge) Krieger. Rest are new records for Eastern Himalaya. All are recorded for the first time from the Mamencho Lake & Sikkim state.