Endothelins are a family of endogenous peptides produced and synthesized mainly by vascular endothelial cells and acts on the vascular smooth muscle. Because of its vasoconstrictor and mitogenic effects it plays a role in the development of vascular diseases.Endothelins was found to be significantly increased in patients with type 1 diabetes mellitus than that of the healthy controls.Endothelin was found to be significantly increased in patients with disease duration more than 10 years than those of disease duration less than 10 years. Endothelin was found to be significantly increased in patients with complications than those without complications.Endothelin was found to be significantly increased in patients with HbA1C more than 9 than those with HbA1C less than 9%.There was a significant correlation between ET-1 and duration of illness (p=0.01), age (p=0.01), cholesterol (p=0.05), HbA1C (p=0.01), microalbumin (p=0.01), PPS (p=0.01) and TG (p=0.01).There was a significant negative correlation between ET-1 and HDL (p=0.05).