The antibody response of turkeys experimentally infected with Mycoplasma synoviae was determined by the serum plate agglutination (SPA), hemagglutination-inhibition (HI), and microagglutination (MA) tests and the enzyme-linked immunosorbent assay (ELISA). No antibody response was detected until 2 weeks postinfection (PI) with the MA test (17% positive), 3 weeks PI with the SPA test (11% positive), 4 weeks with the HI test (21% positive), and 5 weeks PI with the ELISA, and even then, only 16% of the birds were positive. Although at least 89% of the birds were positive by culture, only 58% of the turkeys developed a detectable antibody response.