Appendiceal mucocele is a rare disease and has a clinical picture that resembles acute appendicitis. A correct diagnosis before surgery is very important for the selection of surgical technique(appendicectomy/colectomy)to avoid severe intraoperative and postoperative complications. The work has been reported in line with the SCARE criteria (Agha et al. [23]).We present a case of 70 year old female admitted with chief complaints of right iliac fossa pain intermittent in nature with nausea and generalized weakness since 1 month. With the help of USG and CECT preoperative diagnosis of Appendiceal Mucocele was made. Midline incision Laparotomy was performed. Preoperative diagnosis of Appendix Mucocele changing the course of management has been reported rarely in literature.Intraoperatively a cystic mass of appendix with dimensions 8 cm × 5 cm with broad base and inflamed walls communicating with caecum but without perforation was discovered in right iliac fossa. Extended right hemicolectomy with ileotransverse anastomosis was done. Histopathological diagnosis of Mucinous Cystadenoma with Mucocele was reported. After 6 months of surgery patient is doing well with no postoperative complications.In our opinion every patient more than 50 years old presenting in emergency department with clinical symptoms of acute appendicitis must undergo CT and open surgery should be favoured against laparoscopic surgery.