Diabetes mellitus type II, a cause of preclinical left ventricular dysfunction that can progress to cardiac insufficiency ventricular dysfunction in diabetic patients, is attributed to systemic arterial hypertension, or ischemic cardiopathy. Diastolic ventricular dysfunction takes place during the course of diabetes mellitus. The purpose of the present article is to report on the influence of hyperglycemia on the left ventricular diastolic dysfunction independently of dyslipidemia, obesity, and systemic arterial hypertension, usually present in diabetic patients. Left ventricular diastolic function was studied by Doppler echocardiography in asymptomatic type II diabetic patients without ischemic or valvular cardiopathies, cardiomegaly, or systemic arterial hypertension. Two groups of patients were integrated: patients with and without left ventricular diastolic dysfunction, i.e., groups A and B, respectively. Glycemia, cholesterol, triglycerides, and body mass index (BMI) were determined in each subject. Bivariate statistical tests (Student t, chi-square, or Mann-Whitney U tests) were applied to study the influence of the previously mentioned variables on the ventricular diastolic function. To evaluate the influence of hyperglycemia on ventricular diastolic function separately from dyslipidemia, systemic arterial hypertension, and the influence of obesity, logistic regression, and multivariate statistical analysis were applied. Independently of dyslipidemia and obesity, a relationship was found between hyperglycemia and diastolic dysfunction of the left ventricle in patients belonging to group A (p <0.05, odds ratio [OR] 12.1). No statistical significance was found between glycemia and the diastolic function of the left ventricle in group B patients. Even in type II diabetic patients without cardiopathy, uncontrolled hyperglycemia provokes diastolic left ventricular dysfunction.