Objective To investigate the relationship between constipation and intestinal diseases diagnosed by endoscopy in the elderly patients. Methods The colonoscopic results of 350 elderly patients [aged (72.29±15.71) years] with constipation in our department from July 2009 to July 2013 were collected and retrospectivley analyzed. The endoscopic features of intestinal diseases were analyzed with their disease course and gender. Results Among the 350 cases, the prevelance of intestinal diseases was 60.86% diagnosed by endoscopy, they were colorectitis (26.86%), melanosis coli (13.14%), colorectal polyps (12.00%), colorectal cancer (6.57%), inflammatory bowel disease (1.14%), colonic diverticula (0.57%), intestinal tuberculosis (0.29%) and telangiectasia (0.29%) in order. The prevalences of colorectal polyps and cancer were higher in the male constipation patients than in the female ones (P＜0.05). A higher incidence of melanosis coli was observed in the patients with constipation over 5 years (P＜0.05). Conclusions Constipation in the elderly patients is mainly caused by colorectal diseases. Thus, colonoscopy for these patients is recommended to ensure early detection and treatment, which may be of great help in improving the elderly patients’ life quality.