The authors retrospectively describe the computed tomographic (CT) findings in 35 patients with peptic ulcer disease. Three of eight patients with gastritis or duodenitis had bowel-wall thickening. Ten of the remaining 27 patients had CT evidence of ulcer perforation (n = 2) or penetration (n = 8), four cases of which were unsuspected clinically. Both patients with acute free perforation had pneumoperitoneum, and one showed free extravasation of orally administered contrast material. The precise site of perforation could not be established in either case with CT. The eight patients with ulcer penetration had CT evidence of bowel-wall thickening (n = 3) and inflammatory changes in adjacent soft tissues and organs (n = 8), including the pancreas (n = 4), liver (n = 1), and lesser omentum (n = 1). Ulcer craters were seen in only two. The CT findings of penetration can mimic other disease processes. CT was not useful in detecting uncomplicated peptic ulcer disease.