To determine the prevalence of micro vascular and macro vascular complications in Asian Indian Type 1 diabetic subjects. There has been no major report on the prevalence of vascular complications in Type 1 diabetic patients in India. This study was done in Type 1 diabetic patients, aged < or =20 years at diagnosis of diabetes (n=617, M:F 322:295) with a minimum of 3 year follow-up. Standard diagnostic methodologies were used to test for micro vascular and macro vascular complications of diabetes. Retinopathy was detected in 13. 4% (background diabetic retinopathy 11.2%, proliferative diabetic retinopathy 1.9%, preproliferative 0.31%, maculopathy was seen in 13.3% of retinopathy cases), nephropathy in 7.1%, sensory neuropathy in 3.0%, ischaemic heart disease in 0.5% and peripheral vascular disease in 0.5% of the study subjects. Duration of diabetes showed positive association with retinopathy, nephropathy and neuropathy. Average glycosylated haemoglobin values, at follow up showed an association with retinopathy. Although the glycaemic control was suboptimal in the study group, prevalences of all complications, especially macro vascular complications were lower in Type 1 diabetic patients in this ethnic group, in comparison with the European or American counterparts.