We herein report a case of mucinous cystadenoma of the retroperitoneum successfully removed by laparoscopy. A 45-year-old woman was admitted with a complaint of left back pain associated with re-growth of a retroperitoneal cystic mass, which had been treated by ethanol injection twice since she was 33 years old. Computed tomography and magnetic resonance imaging demonstrated a well demarcated 13.5 cm×9.5 cm cystic mass, in the left retroperitoneum. Under a diagnosis of benign retroperitoneal tumor, laparoscopic resection was performed. To minimize the size of the tumor, as much of its fluid content as possible was aspirated via a trocar, which was then closed using a MINI LOOP RETRACTOR^TM, thereby preventing spillage of the tumor content. This facilitated full mobilization of the tumor, allowing it to be removed successfully. The histopathological diagnosis was mucinous cystadenoma. The patient has been well, without evidence of tumor recurrence, for 17 months since surgery.