A novel hopanoid, 35O-g-6-amino-6-deoxyglucopyranosyl-bacteriohopanetetrol has been isolated from the cyanobacterium Synechocystis sp. PCC 6714.Cyanobacteria of the genus Synechocystis are capable of synthesizing triterpenoids of the hopane series.1 These lipids act as bacterial membrane stabilizers,2 and we reported in a recent paper their localization in the cell wall and in the thylakoids of this cyanobacterium. 3 In this paper, we describe now the full structure of a novel bacteriohopanetetrol glycoside which was the sole bacteriohopane derivative isolated from this microorganism.