Abstract: d:\PDF\.pdfd:\PDF\.pdfObjective : To study the characteristics of primary adenocarcinoma of appendix and methodology of treatment. Methods : We retrospectively analyze the total of 12 cases of primary carcinoma of appendix of all cases of primary malignant of appendix in our hospital from March of 1958 to May of 2003 in terms of clinical characteristics, treatment and prognosis. Results : The incidence of primary adenocarcinoma of appendix is very low. The median age at the time of presentation is 56 (19~68), Male vs. Female is 4 vs. 8. Operations were performed in all patients, most were appenctomy, and the remainders were right hemilcolectomy and palliative operation. Uix of the patients experienced adjuvant chemotherapy, non for radiotherapy. The longest Time to Progression (TTP) is 22 months. Conclusions : Primary adenocarcinoma of the appendix is an uncommon entity. It is very difficult to diagnosis exactly, and is important to perform the differential diagnosis for middle-aged and elderly patients presenting with acute appendicitis. Right hemicolectomy should be performed for colonic type of primary adenocarcinoma of appendix, which has a tendency of metastasize. The role of adjuvant chemotherapy needs to be evaluated in future.