-Context -Weight loss failure is a widely recognized occurrence following Roux-en-Y gastric bypass. Objective -This study aims to identify predictors associated with weight loss failure. Method: It is a retrospective cohort which enrolled 187 subjects who underwent RYGB. Comparisons were made between patients' features at baseline and 24 months after surgery. Results -A weight loss failure rate of 11.2% was found. Advanced age and diabetes were statistically associated with failure. Conclusions -The results found were close to previous reports. As weight loss failure represents an important concern, there is the possibility to perform revisional surgeries, which may emphasize the restrictive or malabsorptive characteristics of RYGB, leading to varied results. It is reinforced that weight loss cannot be used as the unique outcome to evaluate the success of surgery.