Background: Cardiovascular disease is the most common cause of death in patients with diabetes mellitus (DM). Aim of work: To evaluate whether myocardial performance index detects a subclinical impairment of left ventricular systolic and diastolic function in patients with of type 1 diabetes, without coronary artery disease, with or without hypertension. Furthermore, to evaluate whether myocardial performance index and some echocardiographic parameters relate to the metabolic control. Patients and methods : Sixty patients with type 1 diabetes mellitus of varying diabetic duration and 25 age and sex matched healthy controls were studied. All participants had no structural cardiac abnormality. All subjects underwent standard and Doppler echocardiography for the assessment of the Doppler-derived myocardial performance index and cardiac dimensions. In all diabetic patients, a glycated haemoglobin test was also performed.Results: Differences were observed in blood pressure, BMI, and conventional echocardiographic parameters comparing diabetic patients and the controls (p = 0.000). Myocardial performance index was significantly higher in diabetic patients, compared to controls, and was higher in males than females and in diabetic patients more than 3years duration than those less than 3yrs duration. Myocardial performance index significantly correlated to glycated haemoglobin (r=0.46, p = 0.003). Concerning cardiac dimensions, diabetic group showed statistically significant increased LA dimensions (p = 0.033), increased septal hypertrophy (p = 0.010), increased LVPW dimensions (p = 0.003), increased LVEDD (p = 0.000), significant lower systolic function in the form of lower EF % (p = 0.000), and lower FS (p = 0.000). EF was statistically significantly lower in females than in males (p = 0.020). Females had higher LVPW and LVEDD than males (p = 0.028, 0.000 respectively), Diabetic patients with duration more than or equal to 3yrs shows statistical significant higher Aortic, left atrial and PA dimensions more than diabetics with less than 3yrs duration. The cardiac dimensions were correlated to the glycoslated hemoglobin in its different levels but the resulted no statistical significance.Conclusion: An early affection of left ventricular performance was shown by myocardial performance index in patients with type 1 diabetes without coronary artery disease, independent of the presence of hypertension. This index can provide a feasible tool to detect pre-clinical diabetic cardiomyopathy.