Obesity is an inflammatory state related to vascular endothelium dysfunction. It generates a biological situation of hypercoagulability increasing the risk of thrombosis. This prothrombotic condition could be improved by bariatric surgery.The main objective was to analyze the impact of bariatric surgery on cardiovascular risk factors (CVRF) associated with changes in thrombin generation and procoagulant activity of microparticles (MP).We present a prospective longitudinal study including consecutive patients candidate for bariatric surgery. We performed 3 sequential clinical visits: at inclusion, before surgery after completing the modified fasting phase, and 6 months after surgery. We analyzed CVRF, thrombin generation, and MP activity. The data analysis was performed using a logistic regression model to determine changes over time of hemostatic parameters and body mass index (BMI). McNemar test for binary variables was used to analyze the CVRF.We included 94 patients (66 women), with an average age of 45.7 ± 10.1 years. The mean BMI reduction at the end of the follow-up was 15.5 ± 4.2 kg/m2. We detected a statistically significant improvement in CVRF: hypertension, diabetes mellitus, dyslipidemia, and obstructive sleep apnea, as well as a significant reduction in thrombin generation capacity and procoagulant MP activity.Massive weight loss induced by bariatric surgery improves the cardiovascular profile, associated with a reduction in the hypercoagulable status.