There are few data on the risk factors for diabetic nephropathy in the Asian Indian population, although several studies have shown a high prevalence of the disease in this ethnic group. This study also aimed to assess the role of hyperglycaemia and hypertension in the causation and course of nephropathy in this population, which has low rates of obesity. Retrospective analysis of two groups of non-insulin dependent diabetic (NIDDM) patients, one without proteinuria (< 100 mg/day, n = 25) and the other with proteinuria (> or = 500 mg/day, n = 25), matched for age, sex, duration of diabetes and body mass index (BMI) was done to study the factors predisposing to proteinuria and also its progression during a 2 year follow-up. Logistic regression analysis showed that the factors contributory to proteinuria were initial HbA1 and initial systolic blood pressure. The average proteinuria during the follow-up was dependent on the initial and average systolic and diastolic blood pressure values. No correlation was seen between cholesterol or triglyceride values and the change in proteinuria. Creatinine clearance deteriorated in the proteinuric group and this was related to the presence of proteinuria and initial diastolic blood pressure. This study emphasizes the importance of blood pressure in the progression of diabetic nephropathy, even in people who have low BMI. Therefore, good control of blood pressure has an important role to play in the management of this condition.