We report seven cases of pneumatosis intestinalis that was initially detected on routine chest radiographs made in adult bone-marrow transplantation patients. The cases were collected over a 13-month period. The chest radiographs generally underestimated the extent of the pneumatosis, as subsequently seen on plain abdominal films. However, the portions of bowel most extensively involved were those seen on the chest radiographs (transverse colon, hepatic and splenic flexures, stomach). One patient had pneumoperitoneum also. Pneumatosis developed within 6-293 days after transplantation. The cause of pneumatosis intestinalis was multifactorial. Three patients were asymptomatic. Clinical management of all seven patients was altered because of the detection of pneumatosis. The dose of steroids was increased in three patients to treat graft-vs-host disease, antibiotic drugs were given to three patients for enteric pathogens, and bowel rest was prescribed for one patient with mucosal injury from intense chemotherapy and radiation therapy. These cases show that the chest radiograph makes early diagnosis of pneumatosis intestinalis possible in posttransplantation patients.