PURPOSE: To review abdominal ultrasonography in Yersinia Pseudotuberculosis(YP) infection. MATERIALS AND METHODS: From June 1993 through June 1994, abdominal ultrasonograms were reviewed in 36 patients with YP infection. The age of patients was from 4 to 14 years. A diagnosis of YP infection was made on the basis ofisolation of YP from stool (n=15/36, 41.7%) and by documenting at least a minimum agglutination antibody titer of1:160 or greater (n=34/36, 94.4%). RESULTS: Abdominal US findings were identifed in 33/36 (91.7%) of patients with YP infection. US abnormalities included right lower quadrant abdominal lymphadenopathy in 28/36 (77.8%) of cases ;increased bilateral renal cortical echogenecity with renal enlargement, 11/36 (30/6%) of cases ;hepatosplenomegaly, 6/36 (16.7%) of cases ; bowel wall thickening in termnal ileum and cecum, 4/36 (11/1%) of cases ; and ascites, 2/36 (5.5%) of cases. Three patients revealed no abdominal sonographic finding. CONCLUSION: We conclude that abdominal US can help in the diagnosis of YP infection when US demonstrates multiple right lower quadrant abdominal lymphadenopathy, increased renal cortical echogenecity with renal enlargement, hepatosplenomegaly, intestinal wall thickening or ascites.