The goal of the current study was to estimate the prevalence of sleep bruxism (SB) in the general population using a representative sample of 1,042 individuals who answered questionnaires and underwent polysomnography (PSG) examinations. After PSG, the individuals were classified into 3 groups: absence of SB, low-frequency SB, and high-frequency SB. The results indicated that the prevalence of ... [Show full abstract] SB, indicated by questionnaires and confirmed by PSG, was 5.5%. With PSG used exclusively as the criterion for diagnosis, the prevalence was 7.4% regardless of SB self-reported complaints. With questionnaires alone, the prevalence was 12.5%. Of the 5.5% (n = 56) with confirmed SB, 26 were classified as low-frequency SB, and 30 as high-frequency. The episodes of SB were more frequent in stage 2 sleep, and the phasic bruxism events were more frequent than tonic or mixed events in all sleep stages in individuals with SB. A positive association was observed between SB and insomnia, higher degree of schooling, and a normal/overweight body mass index (BMI). These findings demonstrate the prevalence of SB in a population sampled by PSG, the gold standard methodology in the investigation of sleep disorders, combined with validated questionnaires (ClinicalTrials.gov, NCT00596713).