In this paper seven samples of the intestines originated from the naturally infected pigs, macroscopic, histochemically and immunohistochemically were examined. The caudal part of jejunum and ileum were affected. The affected intestine was thickened and dilated. The lumen of the ileum and colon contained one or more blood clots without feed contents. The rectum contained black tarry feces of mixed blood and digesta. The mucosal surface of the affected portion of intestine was markedly thickened without macroscopic erosions. Histological examination revealed: extensive degeneration, congestion, and hemorrhage within the proliferative epitelium, as well as a marked accumulation of the bloody cellular debris above affected mucosa. Clusters of argyrophilic, slightly curved rod-shaped microorganisms in the apical cytoplasm of enterocytes by Warthin-Starry silver stain were demonstrated. Immunohistochemical staining confirmed the presence of L. intracellularis in the apical cytoplasm of hyperplastic enterocytes and in lamina propria. In conclusion, diagnosis of hemorrhagic proliferative enteropathy is based on detection of the histologic lesions and detection of L. intracellularis by Warthin Starry silver stain, as well as by immunohistochemistry, where immunohistochemistry and Warthin-Starry silver method can be a complementary methods to confirm the diagnosis of L. intracellularis infection in pigs.