Purpose : To evaluate the pattern of colonic diverticulosis according to age and sex, and recent trend. Materials and Methods : The authors retrospectively reviewed 120 cases of colonic diverticulosis in 1, 020 patients who had undergone a double contrast barium enema examination between January 1st, 1993, and December 31st, 1995, and analyzed the frequency, size, multiplicity and anatomical site, according to age and sex. Diverticulum size was classified into one of three groups: less than 5mm, 5-10mm, over 10mm in diameter. Results : The Overall incidence of colonic diverticulosis was 120 cases among 1, 020 patients(11.8%) with an incidence 5.3 times higher in males than in females. Peak incidence was in the fifth decade, with 19 cases (15.8%) among males, and after the sixth decade, with four cases(3.3%) among females. Mean age was 57.7 years. Diverticulum size of 5-10mm in diameter was predominant 2% of cases); average diameter was 5-6mm. The incidence of colonic diverticulosis was 5. 1 times more frequent in the right colon(101 cases) than in the left (20 cases). Conclusion : The overall incidence of colonic diverticulosis has continually increased; in addition it has also recently increased slightly in left-sided colon. This is thought to be due to various factors, both congenital and acquired, including longer life with good health care, constipation, irritable bowel syndrome, stress and the tendency of eating patterns to more closely resemble those of the west.