A mobile caecum and ascending colon is a rare congenital abnormality. Its presentation as a cause of right lower abdominal pain in an adult is usually mis-diagnosed as acute appendicitis. A 42-year-old civil servant presented with a 2-year history of recurrent right lower quadrant pain of the abdomen. The pain was sharp in nature and persistent in the last 2 weeks and centered mainly in the right side of the abdomen. No other associated symptoms were noted. Laboratory investigations did not reveal obvious abnormality. A diagnosis of acute on chronic lower quadrant pain of unknown etiology was made. The patient was resuscitated and had exploratory laparatomy. No abnormalities were found other than the caecum and the whole ascending colon, which were unattached to the posterior peritoneum. Appendectomy and caecopexy, using a lateral peritoneal flap were performed. The diagnosis of mobile caecal syndrome should be considered in patients with chronic right lower quadrant pain, and appendectomy and caecopexy offers a great relief.