The authors discuss the problem of venous thromboembolism as a complication of bariatric surgery. They consider obese patients at risk for these complications, even if different opinions exist about this topic in the literature. They report their experience in bariatric surgery consisting of 53 patients submitted to biliopancreatic diversion. Antithrombotic prophylaxis consisted for every patient in elastic bandaging of the lower limbs, preoperative hemodilution, early post-operative mobilization, and subcutaneous heparin. Complications consisted in one popliteo-femoral deep venous thrombosis (DVT) (1.6%), and two pulmonary embolisms (PE) (3.2%) of which one caused patient's death; total morbidity for venous thromboembolism. These results compared with literature are similar with other series of bariatriac surgery and slightly higher than general surgery series. This difference is not however significant. Even in the absence of this significance, thromboembolism, as desumed from more than 2900 cases considered in the literature, remains the main cause of morbidity and mortality in the post-operative course of bariatric surgery patients, deserving particular attention in terms of prevention, also because of difficulty existing in early clinical diagnosis of DVT in obese people. Further studies intended to identify pathogenesis and risk factors of venous thromboembolism in obese people will allow a more correct prophylactic and therapeutic approach.