Primary retroperitoneal mucinous cystadenoma (PRMC) is a rare cystic lesion occurring mostly in women with a histological analogy to ovarian mucinous cystadenoma. The tumor is difficult to detect during early stages because it causes symptoms only when it grows large enough to be palpable or to displace the adjacent internal organs. The primary treatment is resection, but the optimal surgical approach remains poorly known. We report the case of a 41-year-old woman who complained of right-sided intermittent abdominal pain. Imaging studies revealed a right retroperitoneal smooth cystic lesion (50 mm) without invasive features. Laparoscopic resection was then performed. During surgery, a right retroperitoneal mass with no connection to neighboring tissues was found. The tumor, wrapped by retroperitoneal fat tissue, was resected and removed from the body without exposure. Furthermore, histopathological findings indicated PRMC. The patient was discharged without any complications and observed to have no recurrence 6 months postoperatively.