ABSTRACT Recent research has clearly shown that when compared to before surgery, post-bariatric surgery patients are at increased risk for alcohol use disorders and increased alcohol intake. Understanding the mechanisms that contribute to these negative clinical outcomes is of considerable scientific and clinical importance. In the present study, we propose to investigate the extent to which changes in the reinforcement of alcohol lead to increased alcohol intake in post-bariatric surgery patients. We will employ momentary naturalistic assessment, objective continuous alcohol measurement, and laboratory methodology to carefully assess reinforcement using an empirically supported behavior economics-based measure. Additionally, this study is designed as a prospective, longitudinal investigation that will follow bariatric surgery patients from one year to two years after surgery.