BACKGROUND India has world's second largest number of diabetics. Much of the excess mortality among diabetics is because of cardiovascular diseases, including heart failure. Left ventricular diastolic dysfunction (LVDD), the earliest subclinical manifestation of diabetic cardiomyopathy, can worsen to heart failure. Some studies reported relation between LVDD and hyperglycaemia. There are no such studies on Keralite population. Ethnic variations occur in susceptibility to diabetes mellitus and cardiovascular diseases. Our study aims to examine whether LVDD in Keralite diabetics is related to the glycaemic status reflected by HbA1c. METHODS This is a cross sectional analytical study. Thirty diabetics between 21-50 years of age without hypertension, obesity and other comorbidities were selected. Parameters of left ventricular diastolic function (Iso-Volumetric Relaxation Time, ratio of peak velocity of early filling phase to peak velocity of late filling phase, deceleration time and ratio of peak velocity of early filling phase to early diastolic mitral annular velocity) were assessed by echocardiography and pulse wave tissue Doppler imaging. Venous blood HbA1c% (glycated haemoglobin A) was estimated. RESULTS 54.5% of the diabetics had Left Ventricular Diastolic Dysfunction (LVDD). HbA1c levels accounted for 88% variance in LVDD. There was a strong correlation between LVDD and HbA1c levels. CONCLUSIONS There is a strong correlation between LVDD and hyperglycaemia, as reflected by high HbA1c levels. So, rigorous control of blood glucose levels is needed to prevent heart failure in diabetes mellitus.