Three new taxoids, taxuspines X-Z (1-3), have been isolated from stems of the Japanese yew Taxus cuspidata SIEB. et ZUCC. and the structures elucidated on the basis of spectroscopic data. Taxuspine X(1) is a rare example of a bicyclic taxane-related diterpenoid consisting of 6/12-membered ring system with a cinnamoyl group at C-5. Taxuspine Y (2) is one of unique taxoids with 5/7/6-membered ring system, while taxuspine Z (3) is a new taxoid consisting of 6/8/6-ring system with a Winterstein's acid moiety at C-5.