A marine-derived bacterium, Streptomyces misionensis BAT-10-03-123, has produced four new streptenol derivatives, F, G, H, and I (1–4), as well as the known streptenols A and C (5 and 6). Their planar structures were elucidated by detailed analysis of spectroscopic data. The absolute configurations of the new streptenol compounds were determined by chemical and spectroscopic methods, including Mosher’s ester method. All of the compounds were tested for cytotoxicity against four selected cancer cell lines.