A hemagglutination-inhibition test for demonstrating antibodies to Mycoplasma meleagridis is reported. Antigen used in the test was prepared from a hemagglutinating strain of M. meleagridis isolated from a turkey embryo. The antigen, suspended in phenolized saline, could be stored at 50C for weeks and still be effective. Examination of serums from both naturally and experimentally infected turkeys using this test gave results similar to those obtained with a tube agglutination test. The results indicated that the hemagglutinationinhibition test is effective for demonstrating M. meleagridis antibody response in turkeys.