As reported in the foregoing paper, a macrolide antibiotic complex M-4365 produced by Micromonospora capillata MCRL 0940 was composed of at least six components designated M-4365 A1, A2, A3, G1, G2 and G3. The present paper is concerned with the structure elucidation of these components. By physicochemical analyses and chemical procedures, the structures of a series of basic 16-membered macrolide antibiotics, M-4365 A1, A2, A3, G1, G2, and G3 were elucidated. By this study, M-4365 A1, G1 and G2 were found to be novel antibiotics belonging to the 16-membered basic macrolide antibiotic group, while M-4365 A2, A3 and G3 were identical with rosamicin (juvenimicin A3), juvenimicins A4 and B1, respectively.