A case of retroperitoneal air caused by rectal perforation during a double-contrast barium-enema examination is reported. In 9 similar reported cases, radiographic signs included perirectal, mediastinal, and cervical emphysema. Because of the frequent absence of clinical signs, radiographic recognition may be crucial for prompt management. Reported experience suggests that asymptomatic patients with these radiographic findings may be managed with hospitalization and close observation rather than immediate laparotomy.