BACKGROUND: Leaks after laparoscopic sleeve gastrectomy (LSG) are serious complications of this procedure. The objective of the present study was to evaluate the costs of leaks after LSG. SETTING: Private hospital, France. METHODS: A retrospective analysis was conducted on a prospective cohort of 2012 cases of LSG between September 2005 and December 2014. Data were collected on all diagnostic and therapeutic measures necessary to manage leaks, ward, and intensive care unit (ICU) length of stay. Additional outpatient care was also analyzed. RESULTS: Twenty cases (0.99%) of gastric leak were recorded. Fifteen patients had available data for cost analysis. Of these, 13 patients were women (86.7%) with a mean age of 41.4 years (range 22-61) and mean BMI of 43.2 kg/m(2) (range 34.8-57.1). The leaks occurred after 7.4 days (±2.3) postoperatively. Only one gastric leak was recorded for the last 800 cases in which absorbable staple line reinforcement was used. Mean intra-hospital cost was 34398 € (range 7543-91,632 €). Prolonged hospitalization in ICU accounted for the majority of hospital costs (58.9%). Mean additional outpatient costs for leaks were 41,284 € (range 14,148-75,684€). CONCLUSIONS: Leaks after LSG are an expensive complication. It is therefore important to take all necessary measures to reduce their incidence. Our data should be considered when analyzing the cost effectiveness of staple line reinforcement usage.