A choice of many antihypertensive strategies is now offered for the treatment of the hypertensive patient with renal insufficiency. Angiotensin-converting enzyme (ACE) inhibitors appear to be the drugs of choice since they not only lower blood pressure but also reduce some important risk factors that may cause progressive loss of renal function, such as intraglomerular hypertension, angiotensin II (Ang II)-induced glomerular growth, proteinuria and hyperlipidemia. Indeed, several clinical studies now show that ACE inhibitors offer renal protection beyond the lowering of systemic blood pressure. The new class of Ang II receptor antagonists and its first representative losartan has not yet been tested clinically for its renal protective efficacy. The first signs, however, look promising, since losartan appears to induce changes in several identified risk factors to the same extent as ACE inhibitors, such as renal vasodilation, and a fall in proteinuria and serum lipids. The challenge will be to discover the differences between ACE inhibitors and Ang II receptor antagonists and to use them to the future advantage of the renal patient.