Abstract Objective to estimate the prevalence and incidence of diabetes mellitus in a retrospective cohort of older adults, identify the main factors associated with the disease for both periods 2008-2009 and 2016-2017 and describe the prevalence of diabetes according to overweight status. Method a retrospective longitudinal study with 442 community-dwelling older adults (≥65 years old) participating in the FIBRA study (baseline 2008-2009 and follow-up 2016-2017) in Campinas and Ermelino Matarazzo (São Paulo State). Prevalences were estimated and associations were verified using Pearson’s chi-square test or Fisher’s exact test (p<0.05). Crude and adjusted prevalence ratios for sex, age and education were also estimated using Poisson regression. Results the prevalence of diabetes mellitus increased from 21.95% to 27.46% in nine years (p=0.001), and the incidence was 5.51%. At baseline, the prevalence was higher among older adults who were overweight and had a worse perception of health. Overweight status remained associated at follow-up, together with the presence of two or more chronic diseases and the consumption of 3 to 5 snacks/day. Conclusion in 2008-2009, one in five older adults had diabetes and, in 2016-2017, this ratio was about one in four. The importance of being overweight in determining the disease in both periods is highlighted. Educational interventions, expansion of care coverage, greater frequency of care and multi-professional assessment that considers comorbidities, the social and family insertion of the older adult, and their support network are required.