In recent several years, isolation of β-lactam antibiotics including monobactams, a carbapenem and a cephem compound from bacterial strains has been reported1). In this paper, we report the isolation of chitinovorins A, B and C from a bacterial strain identified as Flavobacterium chitinovorum sp. nov. which are characteristic in possessing a formylamino group at the C-7 position of the cephem nucleus.