One hundred thirty two cases of the pathologically proven colorectal cancer at Korea Atomic Energy Research Institute Hospital in the period from January 1973 to June 1980 were analyzed radiologically and clinically. The results were as follows: 1. The colorectal cancer was prevalent in rectosigmoid area and in the fourth to seventh decade of life. 2. The clinical pictures were classified into two groups. The one was rectosigmiod cancer with bowel habit changes. The other was one with no specific symptoms or signs. The clinical pictures of the right colon cancer were rather indirect, chronic and systemic than those of the left one. 3. The roentgenological findings were classified into two groups. The one was rectum and left colon cancer with symmetrical annular narrowing and the other showed trumpet-like proximal dilatation. 4. The most frequent complication was intestinal obstruction. 5. The majority of colorectal cancer was adenocarcinoma. The squamous cell carcinoma and atypical cell carcinoma were most prevalent in rectum, but malignant lymphoma often occured in right colon. The rarest colorectal cancer was atypical cell carcinoma in rectum.