ObjectiveWe sought to assess the potential association between history of bariatric surgery and graft rejection among solid organ transplant (SOT) recipients. MethodsWe conducted a single-center retrospective study of adult (age ≥18 years) SOT recipients (2000-2015) at a large tertiary care transplant network with graft rejection and bariatric surgery history according to the international classification of diseases 9th revision. Data were analyzed using ANOVA, Chi Square, Fisher Exact tests, and logistic regression. ResultsOf 4363 SOT recipients, 72.6% had a history of graft rejection and 55 (1.3%) had a history of bariatric surgery. On univariate analysis, patients with graft rejection were more likely to have a history of bariatric surgery than those without organ rejection (1.5% vs. 0.7%, p=0.015). In multivariable analysis adjusted for age, transplant organ type, and history of calcineurin-based immunosuppression, there was increased odds of rejection among those with a history of bariatric surgery (Odds Ratio (OR): 3.01, 95% Confidence Interval (CI):0.98-4.46, p=0.05). However, when adjusted for body mass index at transplant, the association was attenuated (OR:3.48, CI:0.81-14.9, p=0.10). ConclusionOur single-center data indicate that the relationship between a history of bariatric surgery and graft rejection after SOT may be explained by obesity.