In a multiinstitutional review, data on 396 patients with benign solitary or multiple insulinomas operated on in 15 centers were collected. In these 396 patients, 419 laparotomies (375 primary procedures and 44 reoperations) were performed. The rate of unnecessary laparotomies was 1.7%. Complications occurred after 132 operations (31.5%), requiring 27 reinterventions (6.4%). Ten (2%) patients died within 30 days of surgery. The success rate of first procedures in the centers was 94.9%. After reoperation, all but 2 (99.5%) of these patients were cured. The overall cure rate including those patients who had their primary operations elsewhere was 97.5%.