To assist in the evaluation of inflammatory changes of the affected bowel, we classified the transabdominal ultrasonographic findings into types A-C. We compared the in vivo and in vitro sonographic images to the histopathologic findings of resected specimens. A total of 22 bowel specimens (five normal, 12 with Crohn's disease, five with ulcerative colitis) were examined sonographically with a 3.75-MHz curved and a 7.5-MHz linear array scanner; histologic examination of the same area of tissue was performed afterwards. These three examinations corresponded well to each other. Our classification scheme is useful in quantifying the severity of inflammatory changes in the affected bowel.