Background: There is limited data on the prevalence of eating disorder pathology in morbidly obese patients undergoing Roux-en-Y gastric bypass (RYGBP) and the degree to which this may affect surgical outcome. The present study examined surgical outcome between 2 groups of patients undergoing RYGBP: those with pre-surgical binge eating (BE) and those without pre-surgical binge eating (NBE). Methods: This study tested the hypothesis that the BE group would demonstrate greater pathology on measures of eating pathology, psychological wellbeing, and quality of life than the NBE group both pre- and post-surgery. Results: Compared with the NBE group, the BE group had significantly higher levels of disinhibited eating, and hunger, and significantly lower levels of social functioning at pre-surgery and 6 months post-surgery. The BE group had a significantly lower percentage of excess weight lost than the NBE group at 6 months post-surgery. Conclusions: These findings indicate a less successful outcome for the BE patients compared with the NBE patients. While there were more distinct differences between the BE and NBE groups before surgery, they were largely impossible to differentiate on psychosocial measures at post-surgery.