OBJECTIVES: To evaluate the quality of life (QoL) of diabetic patients and its associated factors.  METHODS: In January to Febrary 2014 patients with diabetes mellitus (DM) were interviewed in cities of Minas Gerais State about sociodemographic, clinical and QoL aspects of. QoL was measured by the EuroQol questionnaire (Eq5D). Descriptive analysis, correlation, linear regression multivariate analyzes were performed. RESULTS: We interviewed 2,620 patients. Of these, 69% were women, 84% had type 2 DM and 10% type 1. The mean age was 61 years (σ = 16). The descriptive system Eq5d scores ranged from -0.1896 and 1.000 (μ = 0.7158; σ = 0.22) and for the visual analog scale from 0 to 100 (μ = 67.5; σ = 22). These values are consistent with the utility values (-0.235 to 0.869) for the general population of Minas Gerais. The mean QoL of diabetic patients was 0.716 (σ=0.22). Multivariate analysis showed that the following aspects significantly decrease QoL of the patients: (I) not being able to do usual activities; (II) bedridden for sickness; (III) worse self-rated health status; (IV) history of arthritis, osteoarthritis or rheumatism; (V) obesity; (VI) depression; (VII) stroke; (VIII) retinopathy; (IX) neuropathy; (X) chronic lung disease; (XI) thrombosis; (XII) need for help to take medicines; (XIII) growing old; (XIV) years on medication; (XV) living alone; (XVI) have been hospitalized in the last 15 days; (XVII) have spent money on supplies for diabetes and (XVIII) not do exercise (p <0.05).  CONCLUSIONS: The interviewed diabetic patients had worse QoL than the general population and the diabetes complications decreases QoL of these patients, which points out to the need for better disease control, monitoring and more educational activities that effectively contribute to the self-care.