Background: The use of metal stents for the treatment of dysphagia due to esophageal malignancy is an important advance because of ease of delivery and their self-expandable property. Obstruction due to tumor overgrowth is a recognized complication, but nonmalignant obstruction in patients with metal stents is rarely reported. Methods: Database records of patients who had esophageal cancer and underwent metal stent insertion were reviewed. Results: A total of 116 patients were seen between October 1993 and October 1997. Four types of metal stents had been used (Ultraflex, Z Stent, Wallstent, and Esophacoil). Detailed follow-up information was available for 81 patients, who constitute the study sample. Forty-nine (60%) stent obstructions were reported, 26 of the 49 (53%) were due to tumor overgrowth and 23 (47%) were not associated with malignancy. Histologic analysis of the nonmalignant obstructing tissue showed granulation tissue (56%), reactive hyperplasia (22%) and fibrosis (22%). Conclusions: Nonmalignant obstruction is a common although infrequently reported complication after placement of metal stents for esophageal cancer. The tissue response of the esophageal mucosa occurred with all 4 types of stents used. No specific characteristic of the stent or prior treatment seems to be related to obstruction of the stent in patients with either nonmalignant obstruction or tumor overgrowth. (Gastrointest Endosc 2000;51:556-9.)