OBJECTIVE Epidemiologic studies that control for potential confounders are needed to assess the independent associations of obstructive sleep apnea (OSA) with metabolic abnormalities. The aim of our study was to evaluate the associations of OSA with metabolic abnormalities among the adult population of Sao Paulo, Brazil. DESIGN AND METHODS Questionnaires were applied face-to-face, full night polysomnography (PSG) was performed, and blood samples were collected in a population-based survey in Sao Paulo, Brazil, adopting a probabilistic three-stage cluster sample method. The metabolic profile included fasting glucose, insulin, and lipid levels. The hepatic insulin resistance index was assessed by the homeostasis model assessment-estimated insulin resistance (HOMAIR ). RESULTS A total of 1,042 volunteers underwent PSG. Mild OSA and moderate to severe OSA comprised 21.2% and 16.7% of the population, respectively. Subjects with severe to moderate OSA were older, more obese, had higher fasting glucose, HOMAIR , and triglycerides (TG) levels than did the mild and non-OSA group (P < 0.001). Multivariate regression analyses showed that an apnea-hypopnea index (AHI) ≥ 15 and a time of oxy-hemoglobin saturation <90% were independently associated with impaired fasting glucose, elevated TG, and HOMAIR . CONCLUSIONS The results of this large cross-sectional epidemiological study showed that the associations of OSA and metabolic abnormalities were independent of other risk factors.