A specific enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to the porcine pathogen Lawsonia intracellularis was developed and evaluated using sera from naive, naturally infected as well as experimentally infected pigs. On the basis of 37 serum samples collected from experimentally infected pigs and 62 serum samples from naturally infected pigs the sensitivity of the ELISA was calculated to 98.0%. The specificity of the test was 99.3%, calculated on the basis of 273 serum samples collected in six herds free of L. intracellularis after medicated eradication. The novel ELISA was a specific and sensitive method for detecting specific antibodies, and may be a good alternative to the existing serological tests for L intracellularis. It may be usable for diagnosis of proliferative enteropathy and for determination of a herd's epidemiologic status.