We report two brothers with Yersinia tuberculosis type IVB infection. The younger brother was hospitalized with severe ileocecalgia and vomiting, and was operated on under the diagnosis of acute appendicitis. Yersinia appendicitis was diagnosed after resection of appendix, cultivation of the stool specimen and examination of agglutinin titration of the serum against Y. pseudotuberculosis type IVB. Seven days after his operation, his older brother was admitted with symptoms of headache, fever, nausea vomoting and erythema. The Stool culture confirmed Y. pseudotuberculosis infection. Surgeons should keep in mind that, in some cases, appendicitis can be due to pathogenic infection by the Yersinia bacteria.