Serological and biochemical studies were performed with 86 Mycoplasma strains isolated from airsacculitis, trachea, eye cavity, oropharynx and cloaca of a total of 50 turkeys raised in two farms in Miyazaki. In addition, 4 strains originating from the oropharynxes of 2 out of 3 turkeys raised in a farm in Tokyo and affected with airsacculitis were examined. Forty-six strains from Miyazaki and one strain from Tokyo were identified as Mycoplasma meleagridis. The remainder, 43 strains, was serologically identified as M. gallinarum (4 strains), serogroup D (5), serogroup I (18) and unidentified (16). Biochemically, M. meleagridis was characterized by being positive for the production of phosphatase and breakdown of arginine. Contamination with M. meleagridis among turkeys reared in many parts of Japan is suggested.