Benefits of ultrasound on diagnosis of specific intestinal obstruction exclusive of due to adhesion, carcinomatosis, paralysis, and unknown origin were investigated in 65 patients in a recent 7-year period. Tumors were seen in 60 percent of patients in cases of colorectal cancers, however, dilatation of the colon were seen in almost cases of those patients. Aspect of colonic dilatation gives us a clue of colorectal cancer. Dilatation of the small intestine and protruded intestine to extraabdominal wall indicated external hernia. Invagination cases were diagnosed easily by multiple concentric sign. Small intestinal anisakiasis were diagnosed with relatively large amount of ascites and corn sign in all cases. Afferent loop obstruction was diagnosed with dilatation of the afferent loop and bile duct. Conversely, we could not obtain any diagnostic clue in internal hernia and volvulus of colon. Ultrasound is very useful in diagnosis of specific intestinal obstruction except for internal hernia and volvulus of colon.