Four steroidal saponins were isolated from the methanol extract of the leaves of Agave ferox. On the basis of chemical and spectroscopic evidence, the structures of these saponins were established as yamogenin 3-O-α-L-rhamnopyranosyl- (1→ 2) –[α-L- arabinopyranosyl-(1→3)-β-D-glucopyranoside; yamogenin 3-O-α-L-rhamopyranosyl –(1→  2 ) [-B-D-glucopyranosyl-(1→4)-6-D- glucopyranoside; gentrogenin 3-O-α-L-rhamnopyranosyl- (1→2)-α-L-arabinopyranosyl- (1→3) - β-D-glucopyranosyl-(1→ 4)-β-D- galactopyranoside and gentrogenin 3-0-a-L- rhamnopyranosyl-(1→2)-B-D-glucopyranosyl(1-→3)-B-D glucopyranosyl- (1→4) -B-D- galactopyranoside. The four saponins were found to possess various molluscicidal activities against Biomphalaria alexandrina snails; the intermediate host of Schistosoma mansoni in Egypt.