Double balloon endoscopy (DBE) was developed for the examination of the small intestine. DBE together with capsule endoscopy have improved the endoscopic approach to the small intestine, and revolutionized the management of small-intestinal diseases. DBE features not only deep intubation of the small bowel, but also the improved control of the endoscope tip, even in the distal small intestine. This improved control is provided by stabilization from the overtube balloon. In this article, we explain how to use DBE effectively and safely. The basic principles of DBE are discussed as well as proper techniques, tips for effective insertion of the double balloon endoscope, proper indications of DBE, and endoscopic therapies in the small intestine.