Diabetic nephropathy is characterised by hypertension and persistent proteinuria. If ineffectively controlled, a progressive decline in renal function can result in end-stage renal disease. Patients with diabetic nephropathy are also at greatly increased risk of cardiovascular disease. Angiotensin-converting enzyme (ACE) inhibitors display additional renoprotective effects beyond systemic blood pressure lowering, perhaps due to reduction in intraglomerular pressure by inhibition of angiotensin II activity. In type 2 diabetics, ACE inhibitors have variable effects, with some studies showing a reduction in microalbuminuria, prevention of the progression to macroalbuminuria and maintenance of renal function. Randomised studies have demonstrated that angiotensin II receptor blockers (ARBs), as well as controlling systemic blood pressure, delay progression of proteinuria in patients with diabetic nephropathy. Telmisartan has a number of features that may make it particularly suitable for the treatment of diabetic nephropathy. In addition to its long duration of action and almost exclusive faecal excretion, its high lipophilicity should assist in tissue penetration. The Diabetics Exposed to Telmisartan And enalaprIL (DETAIL) study was designed to compare the long-term renal outcome of treatment with telmisartan 40.80 mg versus enalapril 10.20 mg (with titration to the higher dose after 4 weeks) in patients with type 2 diabetes, mild-to-moderate hypertension and albuminuria. The primary endpoint is the change in glomerular filtration rate after 5 years' randomised treatment. Secondary endpoints are annual changes in glomerular filtration rate, serum creatinine and urinary albumin excretion, as well as incidences of end-stage renal disease, cardiovascular events, all-cause mortality and adverse events. The groundbreaking DETAIL study revealed that telmisartan conferred comparable renoprotection to enalapril and was associated with a low incidence of mortality.