A new monocyclofarnesane-type sesquiterpene, 3,7,10-trihydroxy-6,11-cyclofarnes-1-ene (1), and a new acorane-type sesquiterpene, 8-(hydroxymethyl)-1-(2-hydroxy-1-methylethyl)-4-methylspiro[4.5]dec-8-en-7-ol (2), were isolated from the culture of Eutypella scoparia FS26 from the South China Sea, along with three known terpenes, 3 -5. The structures of these compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature reports. The isolated compounds 1 -5 were evaluated for their cytotoxic activities against the SF-268, MCF-7, and NCI-H460 tumor cell lines. compound 3 (7.5 mg). Fr.Q eluted with PE/AcOEt 30 : 70 was subjected to CC (Sephadex LH-20; CHCl 3 / MeOH 1 : 1), then followed by CC (RP silica gel C 18 ; MeOH/H 2 O 45 : 55) to yield three subfractions, Frs. Q-1 -Q-3. Fr. Q-1 (25 mg) was subjected to CC (Sephadex LH-20; CHCl 3 /MeOH 1 : 1) to yield compound 4 (18 mg). Fr. R eluted with PE/AcOEt 10 : 90 was further fractionated by CC (Sephadex LH-20; MeOH), followed by CC (RP silica gel C 18 ; MeOH/H 2 O 50 : 50) to yield five subfractions, Frs. R-1 -R-5. Compound 1 (6 mg) was isolated from Fr. R-2 (20 mg) by CC (SiO 2 ; CHCl 3 /MeOH 40 : 1). Fr. T eluted with AcOEt was subjected to CC (Sephadex LH-20; CHCl 3 /MeOH 1 : 1), followed by CC (RP silica gel C 18 ; MeOH/H 2 O 70 : 30) to yield two subfractions, Frs. T-1 and T-2. Compound 2 (4 mg) was isolated from Fr. T-2 (10 mg) by CC (SiO 2 ; CHCl 3 /MeOH 20 : 1). Fr. 5 eluted with PE/AcOEt 90 : 10 was subjected to CC (Sephadex LH-20; CHCl 3 /MeOH 1 : 1), and then purified by repeated CC (SiO 2 ; PE/ AcOEt 20 : 1) to furnish compound 5 (28 mg).