The number of bariatric surgical procedures is still increasing in Germany and also worldwide. According to the German quality assurance study of surgical treatment of obesity, the laparoscopic adjustable gastric banding (LAGB) was the most common bariatric operation with a total of 678 cases between 2004 and 2006 in Germany. In the meantime a high rate of LAGB treatment failures has been reported, so that a high rate of revisional bariatric operations is required. But still the question is open which bariatric procedure can be recommended. The aim of this study is to report the results and follow-up of conversion of failed LAGB to laparoscopic sleeve gastrectomy (LSG). Between 8/2008 and 4/2012 39 patients (31♀/8♂) with a mean age of 43.7 ± 7.8 (26-61) years and a BMI of 47.1 ± 9.1 (30.4 to 67.4) kg/m² had revisional surgery for converting a failed LAGB to LSG. The indications for conversion were dysphagia (38.5 %), weight regain (33.3 %), band slippage (17.9 %), band erosion (5.1 %), band defect (2.6 %) as well as band sepsis (2.6 %). 19 procedures were performed as a one-stage operation and 20 procedures as a two-stage operation. The average operating time was 129 ± 49 (50-312) min. The complication rate was 7.7 %. There were one proximal leak, one gastric sleeve stenosis and one pronounced wound infection. The percent excess weight loss was 23 %, 39 %, 51 %, 52 %, 60 % and 46 % after 1, 3, 6, 12, 24 and 36 months follow- up, respectively. Converting a failed LAGB into a LSG is a revision procedure with low complication rate and promising results, which can be performed as a two-stage as well as a one-stage procedure.