We have experienced an operative case of tuberculous peritonitis with ileus due to diffuse lesion of the small intestine. A 34-year-old man was admitted to another hospital because of abdominal pain and fever. Crohn's disease was initially suspected by colonoscopic findings, and he was treated with corticosteroids. Three months later, Mycobacterium tuberculosis was detected in a stool, and he was then treated as tuberculosis for 6 months. Following chemotherapy, Mycobacterium tuberculosis disappeared, but obstructive symptom did not improve. The patient was referred to the hospital and underwent a laparotomy. Multiple small nodules were disseminated over the serosal surface of the small intestine and mesenterium. At each nodule, intestinal walls converged, making a lump of the intestine and colon. Sharp dissection of the adhesive lesion was performed. An ileus tube was inserted from the gastric wall and induced up to the terminal ileum to prevent re-ileus. A large number of Mycobacterium tuberculosis were found by Ziehl-Neelsen staining of the nodule. Following the surgical treatment, the ileus significantly improved. The postoperative course was uneventful and the patient was discharged from the hospital 39 days after the operation. Mechanical cleaning of the nodules and inserting an ileus tube to prevent recurrence of ileus were helpful to this case in which intestinal resection was difficult because of the diffuse lesion.