Benign duodenal neoplasms (BDNs) are uncommon, and their optimal management remains undefined. We analyzed all cases of BDN treated at our institution during a 10-year period (January 1990 through January 2000). Data are expressed as median (range). Sixty-two patients were treated for BDNs. The results of histologic examination of their lesions were as follows: 36 adenomas, eight Brunner's gland tumors, 10 inflammatory polyps, two hamartomas, and six others. Forty-seven patients were treated nonoperatively, and 15 patients underwent surgery. Lesion characteristics leading to surgical intervention included large polyp diameter and submucosal penetration detected on endoscopic ultrasound imaging. There were no treatment-related deaths. Major morbidity occurred in 2% of patients who underwent endoscopic resection and in 33% of patients who underwent surgery (P = 0.002). Among patients treated for adenomas, seven (19.4%) had a recurrence at a median of 12 (4 to 48) months. Most BDNs can be managed with minimal morbidity using endoscopic techniques. Systematic follow-up of patients treated for adenomas is required.