Metabolic syndrome (MS) plays a key role in the origin of cardiovascular diseases. Studies on the MS in Brazil are recent, and its epidemiology in more isolated regions such as the Amazon is still unknown. The study aimed to estimate the prevalence of MS and associated factors in adults of the Brazilian Amazon. This study was conducted in 2012-2013. It is a cross-sectional population-based study, involving 787 adults randomly selected from the urban area of four cities in the state of Pará, in the Brazilian Eastern Amazon. The participants underwent anthropometric measurements, laboratory examination, and were questioned about their lifestyle. MS was defined by the Joint Interim Statement criteria, using the multiple logistic regression to investigate the potential association of risk factors with the presence of MS. The overall prevalence of MS was 34.1% (95% CI = 30.8-37.4), increasing linearly with the increasing body mass index and age. From 40-49 years of age, MS was observed in about half of the women (46.0%), while men only experienced a high prevalence in the fifth decade of life (43.3%). The low HDL-c (64.4%) and abdominal obesity (58.9%) were higher in women (p < 0.001), while for men, high blood pressure was significantly higher (p < 0.001). Individuals aged 40-59 years old (odds ratio [OR] = 3.35 [95% CI = 2.30-4.90]), ≥ 60 years old (OR = 5.80 [3.63-9.27]), overweight (OR = 4.17 [2.77-6.29]), and obese (OR = 8.82 [5.56-13.98]) were more likely to have MS. The study population experienced high cardiometabolic risk, requiring government efforts to control MS and related risk factors, especially obesity.