We report a case of duodenal neuroendocrine tumor(NET)G1 resected by laparoscopic-endoscopic cooperative surgery (LECS). A 78-year-old woman underwent upper gastrointestinal endoscopy, revealing an 8 mm, rising tumor on the anterior wall of the duodenal bulb. The tumor was pathologically diagnosed as a G1 duodenal NET, by biopsy. Endoscopic ultrasonography showed the tumor might invade the submucosal layer. We performed LECS. The endoscopist marked the dissection line around the tumor and penetrated the duodenal wall. The duodenal wall in the excision area around the tumor was dissected using ultrasonically activated scalpel by the laparoscopist. The closure of the defect in the duodenal wall was performed by the laparoscopic hand-suturing technique. The patient was discharged with no complication on postoperative day 8. The horizontal and vertical margins were free of tumor cells. We demonstrated that LECS for NET of the duodenal bulb anterior wall was useful and safe method to enable appropriate surgical margin and minimum intestinal resection.