The use of alcohol in post-bariatric surgery patients has been examined through a number of studies in the past decade and most have found that increases in alcohol intake, alcohol use disorders, and treatment for problematic alcohol intake increase following surgery. Mechanisms for this increased risk after bariatric surgery have been examined and it appears they may function through reinforcement. Significant changes in the pharmacokinetics (PK) of alcohol occur after bariatric surgery patients and may impact the reinforcement. The current study examined changes in rewarding effects of alcohol and changes that occur in the pharmacokinetics of alcohol following bariatric surgery. Additionally, we examined the association between these changes. Thirty-four bariatric surgery patients were assessed before and one year after surgery. At each time point, they consumed a weight-based priming dose of alcohol and provided blood alcohol concentration and the reinforcing effects of alcohol data. Results show that post-surgery patients report significantly higher maximum concentrations of alcohol and they achieved those levels faster after surgery. The rewarding effects of alcohol were significantly higher after surgery, compared to before. The reinforcing effects of alcohol were associated with level of intoxication. Interestingly, after surgery the association was significantly greater than before. These findings suggest that changes in the PK of alcohol may modify the reinforcing effects of drinking and could play a role in developing problems with alcohol after bariatric surgery.