Esophagogastroduodenoscopy (211,410 examinations) had a complication rate of 1.3/1,000 cases. Duodenoscopy with cannulation was performed 3,884 times and had a complication rate of 21.6/1,000 examinations. Diagnostic coloscopy (25,298 examinations) had a complication rate of 3.4/1,000. Polypectomies during coloscopy (6,124 cases) had a complication rate of 23.3/1,000 cases. Esophageal dilations (13,139 cases) had a complication rate of 4.25 with mercury bougies, and in 9,431 cases metal olives produced a complication rate of 6.1/1,000 treatments. Dilation for achalasia in 1,224 patients produced a complication rate of 18.4/1,000 procedures. Peritoneoscopy (4,404 examinations) produced a complication rate of 5.4/1,000 patients. The value of these diagnostic and therapeutic procedures is now well established but must be weighed against a potential risk of complications.