The association of rectal prolapse and colorectal cancer is quite rare and only a few cases have been reported previously in the literature. It is unclear whether colorectal cancer triggers rectal prolapse.A 77-year-old male patient presented to our emergency department with complete rectal prolapse, and an anterior resection was performed after rectal digital examination revealed a mass. The pathology result came back as mucinous adenocarcinoma in the sigmoid colon and the postoperative period was uneventful.Considering the age group in which rectal prolapse is most commonly seen, and the change in bowel habits, chronic constipation and irritation chronic seen in rectal prolapse may be responsible for the development of rectum cancer, therefore endoscopic screening should not be overlooked in rectal prolapse cases.Anorectal emergencies, Colon cancer, Rectal prolapse.