OBJECTIVES: The aim of this study was to estimate the social cost of the three main bariatric surgery techniques used for the treatment of morbid obesity: gastric banding (GB), gastric by-pass (GBP), and sleeve gastrectomy (SG). METHODS: The study was designed as longitudinal multicenter survey. Adult patients in charge to 6 Hospital Centers in Italy have been enrolled at the time of the intervention and followed up to 1 year. Direct medical costs have been estimated using tariffs for laboratory tests, diagnostic exams, visits, and prices for drugs. Inpatient cost data have been collected at the Center level, as well as the costs of intervention. Non medical costs included costs for travel and accommodation, domestic help and informal care. The loss of productivity of patients have been estimated using the human capital approach. Costs are reported as mean (± standard deviation) in Euro 2013. RESULTS: