Background: Recent studies have shown that being overweight or obese is associated with a higher risk of periodontitis. However, the literature offers an insufficient number of published reports regarding the effect of bariatric surgery on oral health. As such, the present study aims to determine the association between periodontal status and being over-weight/obese in prebariatric and postbariatric surgery populations of Brazil. Methods: Three hundred forty-five participants between 18 and 60 years of age, from both sexes, were grouped according to prebariatric or postbariatric surgery and underwent a complete periodontal examination. Biologic, demographic, and behavioral variables were analyzed in a Poisson regression model. Results: Considering the timing of bariatric surgery, the sample was divided into three groups: PRE-OP (preoperative, n = 133), POS-OP1 (postoperative <= 6 months, n = 72), and POS-OP2 (post-surgery >6 months, n = 140). Regardless of the type of surgery (PRE-OP, POS-OP1, POS-OP2), the prevalence of periodontitis proved to be high (81.45%). There was a statistically significant difference in the prevalence of periodontitis among the PRE-OP, POS-OP1, and POS-OP2 groups (P=0.040). In the Poisson regression model, after adjusting for biologic, demographic, and behavioral risk variables, only bleeding on probing remained significantly associated with the prevalence of periodontitis (P<0.001). Conclusion: Differences in periodontal condition were observed in individuals at different times of the bariatric surgery, showing a high prevalence of periodontitis in both preoperative and postoperative follow-up. J Periodontol 2012;83:257-266.