Epicardial fat thickness (EFT) has emerged as a marker of cardiometabolic risk, but its clinical use warrants proper knowledge of its distribution and associations in populations. We aimed to describe the distribution of EFT, its demographic correlates and independent associations with diabetes, hypertension and metabolic syndrome (MS) in free-living Brazilian adults. From the baseline echocardiography of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)—a cohort study of civil servants aged 35–74 years—EFT was measured from a randomly selected sample of 998 participants as the mean of two paraesternal windows obtained at end systole (EFT_syst) and end diastole (EFT_diast). From the 421 individuals free of diabetes, hypertension and MS, we defined EFT reference values and the EFT_syst 75th percentile cut-off. Median EFT_syst was 1.5 (IQR 0–2.6) mm; a large proportion (84 %) had EFT_diast = 0. EFT was higher in women and lower in blacks, and increased with age and BMI. Although EFT was higher in those with diabetes, hypertension, and MS, EFT associations were reduced when adjusted for age, sex and ethnicity, and were non-significant after adjusting for obesity measures. In conclusion, the amount of EFT in this large multiethnic population is smaller than reported in other populations. EFT reference values varied across demographic and clinical variables, EFT associations with cardiometabolic variables being largely explained by age, sex, ethnicity and central obesity. Although EFT can help identify individuals at increased cardiometabolic risk, it will likely have a limited additional role compared to current risk stratification strategies.