Background: Obesity has reached epidemic patterns and constitutes a serious public health problem due to co-morbidities and the impact on life quality of affected individuals. Bariatric surgery appears as one of the most recommended treatments; however much has been known about the effects of this intervention on the functional performance of the organism as a whole. Objective: To characterize the oral health of adults submitted to bariatric surgery, before and after the intervention, with emphasis on the performance of masticatory function. Methods: A prospective observational cohort study conducted in a public reference service to the treatment of obesity in the city of Recife, State of Pernambuco. The data were obtained during the first half of 2011, through interview, intraoral physical examination and evaluation of masticatory function. Statistical treatment adopted was a CI of 95% and the chi-square test. The collection was conducted in three stages, with initial assessment in the preoperative and follow-up at 60 and 180 days. Results: The sample consisted of 20 volunteers, aged between 23 and 58 years and mean BMI of 43.2 ± 2.8. When compared the pre-operative to the control periods, there were significant differences for variables with decreased tendency towards spontaneous gingival bleeding and increased tooth hypersensitivity and tooth mobility (p < 0.05). Regarding the masticatory function, we found significant differences for most of the variables investigated, except in the coordination of move-* Corresponding author. P. V. Tavares et al. 88 ments and breathing during this function. Conclusion: The performance of masticatory function shows differences in pre-and postoperative periods for bariatric surgery.