A new iridoid glucoside, sesinoside (1), was isolated from the seedlings of Sesamum indicum. The structure of 1 was elucidated by spectroscopic analyses and by methanolysis of 1, which produced the known compounds, phlorigidosides C (2) and (6Z)-foliamenthic acid methyl ester (3). This is the first report of an iridoid glucoside with 3