A new steroidal saponin was isolated from the leaves of Sansevieria cylindrica. Its structure was established as (3beta,12beta,15alpha,25S)-26-(beta-D-glucopyranosyloxy)-22-hydroxyfurost-5-en-3-yl 12-O- (6-deoxy-alpha-L-mannopyranosyl)-15-O-(6-deoxy-alpha-L-mannopyranosyl)-beta-D-glucopyranoside. The structural identification was performed using detailed analyses of (1)H and (13)C NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR, HMBC and HMQC) and chemical conversions. The steroidal saponin showed no haemolytic effects in the in vitro assays and demonstrated inhibition of the capillary permeability activity.