Cobalt (Co)-C-60 mixed clusters were produced by the combination of laser vaporization and molecular beam methods. Cationic Co-n(C-60)(m)(+) clusters were produced predominantly with the compositions (n, m) = (0-1, 1), (1, 2), (1, 3), (2-4, 4), and (5, 5). Both mass spectrometry and a chemical probe method have revealed that compositions of (1, 3) and (4, 4) correspond to a tricapped planar structure and a tricapped trigonal pyramid structure, respectively, in which each Co atom is surrounded by three C-60.