IPVS 2008: Ileitis or proliferative enteropathy is a common infectious disease endemic in most of Spanish farms. Ileitis, even in subclinical form produces a negative impact on both growth performance and farm economics. An oral ileitis vaccine against Lawsonia intracellularis is now approved in many countries worldwide. The aim of this study was to evaluate under field conditions ileitis vaccination impact on growth performance, carcass uniformity and economics in a large Spanish farm.