Two new acetylenic alcohols (1-2) and a new dihydrothiopyranone (3) were isolated from the tropical sponge Reniochalina sp. Their structures were determined by spectroscopic and chemical methods to be (3R)-hydroxyoctatriacont-(4E)-en-1-yne (1), 5-hydroxyheptatriacont-(3Z)-en-1-yne (2) and 2-hexadecyl-2,3-dihydrothiopyran-4-one (3). The acetylenic alcohol (1) exhibited significant growth inhibitory effect against human tumor cell lines.