Objective To study the chemical constituents from the stems of Marsdenia tenacissima.Methods The chemical constituents were isolated by various column chromatography and their structures were identified by spectral and chemical analysis.Results Two pregnane glycosides were isolated from the stems of M.tenacissima and identified as3-O-β-D-glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β-D-allopyranosyl-(1 →4)-β-D-oleandropyranosyl-11α-Otigloyltenacigenin B,named as tenacigenoside I(1)and 3-O-β-D-glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-β-Dallopyranosyl-(1→4)-β-D-oleandropyranosyl-11α,12β-di-O-acetyltenacigenin B,named as tenacigenoside K(2).Conclusion Compound 1 is a new compound,1H-NMR and 13C-NMR data of compound 2 are reported for the first time.