The structure of the steroidal saponin, convallasaponin-D, ³⁾C₅₀H₈₂O₂₁, mp 264-265°, [a]²¹_D : -66°, which was isolated from the flowers of Convallaria keisukei MIQ., Japanese lily of the valley, was studied and elucidated as rhodeasapogenin (1)-β-D-glucopyranosido, (3)-α-L-rhamnopyranosyl (1_rha→2_xyl)-β-D-xylopyranosyl (1_xyl→3_rha)-α-L-rhamnopyranoside.