Older populations are in high risk of nutritional inadequacy and monotonous diet, and the assessment of dietary diversity can be a practical measure to indicate groups at nutritional risk. Our aim was to explore the dietary diversity of older adults enrolled in primary care services in Brazil, and to evaluate their associated factors. In this cross-sectional study, we evaluated the dietary diversity score (DDS) of 581 participants (≥ 60 years) registered in primary care services. All foods mentioned in a 24h-Food Recall were classified into 10 groups, and factors associated with the DDS were analyzed using hierarchical linear regression models in 2 blocks: 1) sociodemographic; 2) health conditions and lifestyle. The mean DDS was 5.07 (± 1.34) and 67.5% of the sample reached the minimum dietary diversity (≥ 5 groups). In the final model, income, previous diagnosis of cancer and sporadic intake of alcohol were positively associated with DDS, while cognitive decline, sedentary lifestyle and anorexia of aging were negatively associated with DDS. These findings show that entire structural, economic, and social system needs to facilitate access to quality food, adequate places and conditions for the practice of physical activity, and policies regarding tobacco and alcohol abuse, in addition to nutritional guidance.