Four steroids have been isolated from the subterranean parts of Smilax nipponica Miquel (Liliaceae). The structures of these compounds were characterized on the basis of chemical and speectral data. They were $eta$-sitosterol, $eta$-sitosterol-3-O-$eta$-D-glucopyranoside, neotigogenin-3-O-$eta$-D-glucopyranoside and a new steroidal saponin designated as smilanippin A which was elucidated as neotigogenin-3-O-$eta$-D-fucopyranosyl(1$ ightarrow$6)-$eta$-D-glucopyranos ide.