This study compared the use of health services and medication, screening test coverage, characteristics of primary care, and health behaviors in 370 diabetics 45 years or older according to sources of care: private health policyholders regardless of place of residence; residents in areas covered by the Family Health Strategy; and individuals covered by a "traditional" Primary Care Unit. The study used data from the 2nd Adult Health Survey in Belo Horizonte Metropolitan Region (2010), Minas Gerais State, Brazil. Use of health services, use of medication, coverage of follow-up tests, alcohol abuse, and smoking did not differ significantly according to source of care. Prevalence rates for insufficient leisure-time physical exercise and sedentary lifestyle were higher among individuals covered by the Family Health Strategy or "traditional" Primary Care Unit. The primary care characteristics (access, comprehensiveness, continuity, and family focus) performed better among individuals with private health insurance, even after adjusting for age, sex, and schooling. The study identified two main challenges for the Brazilian Unified National Health System in managing patients with diabetes in the city of Belo Horizonte: the promotion of physical exercise and reorganization to improve performance in primary care, especially in access to medical appointments.