A novel 22-homo-23-norcholestane trisaccharide, which showed an unique inhibitory pattern on cyclic AMP phosphodiesterase, was isolated from the bulbs of Ornithogalum saundersiae. The structure was determined by extensive 2D NMR analysis and hydrolysis.The cyclic AMP phosphodiesterase inhibition test provides a useful means for the screening of biologically active compounds present in natural sources. Previously, we have reported the structural elucidation of several new cholestane glycosides with potent inhibitory activity on cyclic AMP phosphodiesterase isolated from the methanolic bulb extract of Ornithogalum saundersiae. Further analysis of the extract led to the isolation of a novel 22-homo-23-norcholestane trisaccharide (1). This communication refers to the structural determination of the new constituent and its unique inhibitory pattern on cyclic AMP phosphodiesterase.