Chemical investigation of an Okinawan marine soft coral resulted in the isolation of one new compound (1) and five known cholic acid type keto-steroids 2–6 possessing enone or dienone A-rings and desmosterol (7). The structures of all compounds were elucidated from spectral data, mainly by 1D and 2D NMR techniques, mass spectra, comparison of NMR data with those of reported compounds, and by chemical transformations. Compounds 1–7 showed potent cytotoxic activity.