Lanyamycin (1/2), a secondary metabolite occurring as two epimers, was isolated from the myxobacterium Sorangium cellulosum, strain Soce 481. The structures of both epimers were elucidated from HRESIMS and 1D and 2D NMR data and the relative configuration of their macrolactone ring was assigned based on NOE and vicinal ¹H NMR coupling constants and by calculation of a 3D model. Lanyamycin inhibited HCV infection into mammalian liver cells with an IC₅₀ value of 11.8 µM, and exhibited a moderate cytotoxic activity against the mouse fibroblast cell line L929 and the human nasopharyngeal cell line KB3 with IC₅₀ values of 3.1 and 1.5 μM, respectively, and also suppressed the growth of the Gram-positive bacterium Micrococcus luteus.