Purpose of this study is to know incidence of Mucocele of appendix amongst cases of acute apppendicits operated at an Institution. Mucocele of Appendix occurs when there is abnormal accumulation of mucus within the appendix leading to dilation of appendiceal lumen by mucus. The disease is considered as a rare lesion of the appendix, which is found in 0.2 to 0.3 % of the appendectomies. The course and prognosis of mucocele related to the histological subtypes. Preoperative diagnosis is difficult due to non-specific clinical manifestation and 50% are discovered incidentally at surgery. Patient may present with pain in lower right quadrant of abdomen and surgeon may mistake it for acute appendicitis. Treatment is always surgery and depends on the integrity and size of the appendix base and on the histological type of the disease.