Appendiceal mucocele is a rare condition encountered it only 0.07-0.4% of all appendectomies. The male to female ratio is 1:4 and an average age at the time of diagnosis is over 50 years. Mucocele of the appendix is defined as appendiceal obstruction leading to lumen distension with accumulation of mucoid material. The disease ranges from benign forms to malignant cystadenocarcinoma. The cause of the obstruction may be classified based on histology into four groups. These groups include simple mucocele, mucosal hyperplasia, cystadenoma, and cystadenocarcinoma. Abdominal ultrasound and CT scan may suggest the diagnosis. The authors discuss two cases of simple appendiceal mucocele. A 48-year-old man presented with acute right lower quadrant pain. Ultrasound examination was performed and the structure in the right iliac fossa was reported as an periappendiceal abscess. The patient underwent acute exploratory laparotomy, which revealed an appendiceal mucocele filled with gelatinous material. It was performed ileocoecal resection. A 65-year-old man presented with abdominal distension and discomfort of several week duration. At laparotomy, a smooth cystic tumor of the appendix was found. This patient underwent appendectomy alone. Pathology revealed an simple appendiceal mucocele.