An intragastric implant comprises an anchor and a therapeutic device or a diagnostic device. The anchor is adapted to extend between the fundus and the pyloric valve of a stomach, to be retained without attachment to the stomach wall, and to anchor the device within the stomach with a relatively stable position and orientation. The therapeutic or diagnostic device is adapted to extend from the esophagus or stomach to the intestines or stomach. The therapeutic or diagnostic device, when extending into the esophagus, will be slidably received through the gastroesophageal junction and, when extending into the intestines, will be slidably received in the pyloric valve.