: Cardiovascular complications are the most common cause of mortality and morbidity in diabetic patients. Therefore, the aim of antidiabetic therapy should not only be to provide glucose regulation but also to protect patients from complications and related mortality. Brain natriuretic peptide (BNP) is a peptide secreted as a result of myocardial stress. BNP levels increase under conditions of increased myocardial stress, such as heart failure. It is an important marker not only at the time of diagnosis but also during follow-up. In our study, we aimed to evaluate BNP levels and thus, the factors affecting the risk of developing heart failure during the course of diabetes. : This study was conducted at the diabetes outpatient clinic of the University of Health Sciences, Haseki Training and Research Hospital. A total of 252 patients met the inclusion criteria and were enrolled in the study. All study participants were patients with a confirmed diagnosis of type 2 diabetes. Laboratory parameters, including BNP values, comorbidities, and anamnesis data, were recorded. : The mean BNP levels were significantly lower in patients using metformin and pioglitazone. Other antidiabetic medications were not associated with BNP levels. BNP levels were positively correlated with age and diabetes duration and negatively correlated with hemoglobin levels. According to regression analysis, age, metformin use, and hemoglobin levels were found to independently affect BNP levels. : Our findings suggest that metformin could potentially play a significant role in preventing the development of heart failure in diabetic patients currently not experiencing this complication owing to its favorable effects on myocardial stress. This suggests metformin's potential in preventing heart failure in type 2 diabetic patients.