Three triterpenoidal saponins were isolated from the stem bark of Cariniana rubra Gardner & Miers (Lecythidaceae). The saponins reported are monodesmosides and a bidesmoside derivatives from the triterpene 2alpha ,3beta ,23-trihydroxy-12-oleanen-28-oic acid (arjunolic acid). The proposed structures are 28-b -glucopyranosyl-23-O-acetyl arjunolic acid 1, 3-O-beta -glucopyranosyl arjunolic acid 2 and 28-O-[ alpha -Rhamnopyranosyl-(1-> 2)-beta -glucopyranosyl] -23-O-acetyl arjunolic acid 3. The structures were elucidated mainly from its NMR spectral data. Compounds 1 and 3 are described for the first time.