Aim. The aim of this study was to estimate the prevalence of diabetes and its associated risk factors in adults from Brasilia, Brazil. Methods. The present cross-sectional population-based study consisted of interviews with individuals aged 18-65 years. Participants were selected through two-stage probability sampling by clusters and stratified by sex and age. Demographic and clinical data were collected directly with participants from February to May 2012. Self-reported diabetes prevalence was calculated at a 95% confidence interval (CI). Prevalence ratios (PR) were adjusted by Poisson regression with robust variance. Results. In all, 1,820 individuals were interviewed. Diabetes prevalence in the adult population of Brasilia was 10.1% (95% CI, 8.5%-11.6%). Variables associated with diabetes were an age between 35 and 49 years (PR = 1.83; 95% CI, 1.19-2.82) or 50 and 65 years (PR = 1.95; 95% CI, 1.17-3.23), hypertension (PR = 4.04; 95% CI, 2.66-6.13), respiratory disease (PR = 1.67; 95% CI, 1.11-2.50), cardiovascular disease (PR = 1.74; 95% CI, 1.15-2.63), and pain/discomfort (PR = 1.71; 95% CI, 1.21-2.41). Conclusion. Diabetes is a prevalent condition in adults living in Brasilia, and disease risk increases with age and comorbidities. Future health policies should focus on screening programs and prevention for the more vulnerable groups.