Eight sesquiterpenoids, named Ferulaeone A-H (1-8), and seven known sesquiterpenoid derivatives were isolated from the roots of Ferula ferulaeoides (Steud.) Korov. Their structures were established by comprehensive spectroscopic analysis, and biosynthetic pathways leading to these compounds were proposed. The cytotoxicity of all these isolates against HepG2, MCF-7, and C6 cancer cell lines was evaluated and compounds 6-11, 13 exihibited various degrees of cytotoxic effect. Among them, compounds 9-11 displayed the highest potency against C6 with IC(50) values 34, 36, and 31 μM, respectively.