Background and objective: Diabetic patients could be at increased risk of functional disability, which needs good control of blood glucose and other risk factors and the quality of life of diabetic patients especially those who had complications is remarkably lower than the quality of life of the general population. This study was conducted to assess the quality of life of diabetic patients in its different domains from the patient's perspective in Erbil city. Methods: In this cross-sectional study, 160 diabetic patients were randomly selected from Layla Qassim diabetic health center. The WHO (WHO QOL-BREF) questionnaire was used as the main tool for data collection, which included26 questions on four domains of health-related quality of life (physical, psychological, social and environmental domains). Results: Around 49% of the patients had checked their blood sugar regularly and had better scores in the social domain (P = 0.036). Diabetic patients of all age groups had low scores in all domains of quality of life, with the lowest mean score in the psychological domain. Females reported significantly higher scores in the environmental domain (P = 0.001). Patients with insufficient monthly family income had lower scores in the social (P = 0.001), psychological (P = 0.031) and environmental (P = 0.039) domains. There was no obvious statistical association between clinical characteristics of the patients and the quality of life domains. However, those with complications had lower scores in the psychological domain, with a higher proportion (P = 0.016) of complications in females. Conclusion: All domains of quality of life are affected by diabetes mellitus, with no clear, consistent statistical association between clinical characteristics of the patients and the quality of life of various domains, which emphasize the need for more multidisciplinary team action for more patient`s education and self-care.