© Copyright Health Sciences University Bakırköy Sadi Konuk Training and Research Hospital. This journal published by Logos Medical Publishing. Licenced by Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)Objective: Subclinical appendiceal mucinous neoplasms (AMNs) may accompany abdominal malignancies which must be considered during colectomies. We aimed to evaluate the treatment and follow-up approach to the patients in whom incidentally appendiceal mucinous neoplasm detected following right hemicolectomy performed for abdominal malignancies. Method: The records of the patients who underwent right hemicolectomy due to benign or malign conditions in our general surgery clinic between January 2016 and December 2019 were analyzed. After the exclusion of the patients who had undergone hemicolectomies due to benign causes and appendiceal pathologies detected before the operation, the records of remaining patients' were evaluated. The patient records who underwent right hemicolectomy for gastrointestinal or gynecologic malignanacies were analyzed. The patients whose pathology results were reported as AMNs were included in the study. The incidence of AMN was analyzed and compared with the literature. Results: Hundred and sixty-seven of the 214 patients with gastrointestinal or gynecologic malignanacies were included in this study. Eighty patients were female and 87 were male. The mean age was 63 (23-95) years. The incidence of AMN was 2.9% in patients who underwent right hemicolectomy for malignity in three years period. According to the pathology reports; 3 patients (60%) had appendiceal mucinous neoplasia, one patient (20%) appendiceal mucinous cystadenocarcinoma and one (20%) appendiceal carcinoid tumor. Conclusions: IIncidentally detected AMN is a rare entity and should be considered during the right hemicolectomy operations of different malignancies. Resections must follow principles for malignancy surgery. The preoperative evaluation of the patients needs attention, their postoperative treatment must be planned according to the pathology reports and the patients must be followed for any potential accompanying colorectal tumors.