Morphological, cultural, biochemical, and physiological characteristics of 112 strains of coryneform bacteria were examined. Coryneform bacteria were taxonomically divided into seven groups on the basis of the combination of the characteristics of gram-stain, motility, presence of metachromatic granules, pleomorphism, effect of citrate on cell form, acid formation from carbohydrates, assimilation of organic acids, hydrolysis of gelatin, extracellular DNase, urease, and cell wall composition.