The entirety of the colon is examined best by roentgenology and the barium enema examination is generally regarded as the procedure of choice. One hundred and seven cases of tumor of the colon and rectum were proved by surgery or biopsy at Korea General Hospital from January 1970 to April 1974., and it distinguished 61 cases of malignancy of the colon and rectum and 46 cases of benign tumor. The results summarized are follows: 1. Incidence of tumor in the colon and rectum is morre common in male; male to female ratio is 2.2:1 and 1.6:1 in malignant and benign tumor respectively. 2. Peak age incidence of benign tumor is 3-4 decades younger than malignant that 5th decade. 3. The most frequent complaint is melena or tarry stool in both benign and malignant colonic tumors. 4. Twenty-four per cent of benign tumor are found out incidentally at general check-up examination. 5. Sixty-nine per cent of malignant tumor occur in the sigmoid colon and rectum. The rectum is affected maligna cy of 57 per cent. 6. Accuracy of barium enema examination in diagnosis of cancer of the colon and rectum is 94 per cent and that in benign tumor is 28.5 per cent. 7. The most frequent roentgenological findings of colonic malignancy forms 75 per cent of encircling type. 8. The greater part of malignancy of the colon is adenocarcinoma (95%) and adenomatous polyp have a majority in benign tumor (85%).