The serologic response of Rio Grande wild turkeys (Meleagris gallopavo intermedia) to Mycoplasma gallisepticum (MG) was determined. Free-ranging turkeys were caught in southern Texas, shipped to the University of Wisconsin, Madison, and housed in isolation facilities. Fourteen birds were exposed to MG, by intratracheal and intranasal inoculation. Eight birds received sterile broth only. Two wk prior to the end of the experiment, MG exposed turkeys were stressed by challenge with a serologically unrelated mycoplasma. Serum from all exposed birds reacted positively for MG antibody by the rapid plate agglutination (RPA) procedure within 2 mo postexposure (PE) and all but one remained positive for 14 mo PE. Less than one half of the exposed birds developed positive MG antibody titers detectable by the hemagglutination inhibition (HI) test within 2 mo PE, and by 10 mo PE, none had positive titers. Antibody was detected by the HI test in two of 11 infected turkeys, 14 mo PE, and titers increased significantly within 2 wk. MG was isolated from tracheal swabs from two infected birds 2 mo PE, but attempts thereafter failed. However, at the termination of the experiment 15 mo later, MG was isolated from lung tissue of three of 11 exposed turkeys and from a blood clot found in the lower trachea of one bird.