The evidence from recent clinical outcome trials in arterial hypertension (AH) and the treatment guidelines from national and international authorities have placed a clear emphasis on "tight" blood pressure (BP) control. This has been particularly well illustrated in the treatment of patients with diabetes mellitus and AH where "tight" BP control clearly improves the outcome with reduced numbers of fatal and non-fatal cardiovascular events. Whilst the clinical trials in AH have identified benefits through BP reduction with a range of antihypertensive drugs there is a considerable volume of evidence to suggest that the optimal treatment for diabetic nephropathy and microalbuminuria should be based upon ACE inhibition. It is widely held that inhibition of intra-renal renin angiotensin systems leads to greater benefit than can be achieved by hemodynamic changes alone. Thus, management of AH and nephropathy in both DM and other forms of renal disease revolves around BP reduction through an ACE inhibitor-based treatment regimen. Where there is renal failure it may be prudent to administer a drug such as spirapril which has non-renal elimination mechanisms and which has been shown to have no accumulation problems or increased adverse effects.