Yersinia enterocolitica is a bacteria from family enterobacteriacea that causes acute diarrhea mesenteric lymphadenitis, septicemia, exodative pharyngitis, secondary arthritis and erythema nodosum.Infectious diarrhea is considered as the most prevalent symptom of Yenterocolitica infection among children.During the Present study, 527 and 300 fecal samples were collected from patients with diarrhea, admitted at Qods and Bou-Ali Hospitals respectively, Located at the city of Gazvin, Iran. The smaples were examined for the containment of Yersinia ~ijterocolitica using CIN -agar, selective media and cold enrichment media. Results showed 7 positive samples, all were gathered from infunts. No Yersinia Sp. isolated from adult specimens.For comparison, two other pathogenic bacteria were included in our study, i.e. salmonella and Shigella.Sensitivity of the bacteria was tested againts 13 types of antibiotics by curby -Bayer method after isolation and the results are showed in the present study.