Proliferative enteropathy of pigs (PPE; ileitis, lawsoniosis) is one of the most common, relatively new and little-studied gastrointestinal diseases of pigs which cause significant economic damage to the pig industry worldwide. The causative agent of ileitis is Lawsonia intracellularis, a gram-negative intracellular bacterium. The incubation period lasts from two to three weeks, the infection has a high degree of infection. The pathogen is transmitted from animal to animal by oral and fecal route. In order to study the manifestations of proliferative enteropathy of pigs on farms in Ukraine, we surveyed 32 farms in 13 regions. The course of PPE was usually observed with symptoms of gastrointestinal disorders, but the disease brought significant economic losses. A characteristic symptom of the chronic course in the studied farms of Ukraine is a slow but progressive weight loss of animals and, as a result, diarrhea and loss of appetite. Clinical signs of ileitis depend on the form of the course. There are three main forms of ileitis: chronic form — intestinal adematosis, acute — hemorrhagic enteropathy and subclinical form. According to our research, the acute form is manifested by pale skin and signs of anemia, hemorrhagic diarrhea and sudden death of the animal. Pigs weighing more than 70 kg suffer the most. The pathological picture characteristic of PPE was observed already at the age of 33 days; 62.5% of the dead piglets aged 33 to 102 days were affected by Lawsonia, which was confirmed by laboratory tests. Pathological examination was observed in the dead pigs of the rearing and fattening group: duodenum — part initially covered with mucus-fibrin; ileum — thickening of the walls, on the serous membrane dark red grooves like a mosaic, dark blood, blood coagulates cylindrical forms; mucous membrane is uneven, thickened, intensely red; colon — stretched through gases, blood dark with coagulates in the lumen; rectum — the contents are thick to semi-liquid, dark red; mesenteric lymph nodes — enlarged and hyperemic. Pathohistological changes in the intestine varied. In some parts of the intestine, there were characteristic of ulcerative necrotic ileitis, and in others — for proliferative enteropathy.