Since January 1(st) 2005, the situation of bariatric surgery has been examined in Germany. The data are registered in cooperation with the An-institute of quality control in surgery at the Ottovon-Guericke-Universitat Magdeburg. The data registration occurs in an internet on-line data bank. Application for participation in this study is available on our correspondence address. All hospitals carrying out bariatric surgery are asked to take part in this study.