We discuss the evidence supporting the use of angiotensin-converting enzyme inhibitors (ACEI), angiotensin II type 1 receptor blockers (ARB), or the combination of both in children with chronic renal disease. Several large-scale, prospective, randomized studies with clinical end points have been performed in adult patients, but studies in children are relatively scarce. In adult patients with chronic renal diseases, ACEI clearly delay the progression of chronic non-diabetic renal diseases, and nephropathy in patients with type 1 diabetes. The benefits of ACEI are most apparent in glomerular diseases with marked proteinuria but extend also to kidney diseases with lower proteinuria. This notion is also supported by several smaller or retrospective trials in children. Therefore, ACEI should be given to children with chronic renal diseases, particularly if high blood pressure and/or proteinuria are present. In adults, large-scale trials have documented that ARB exert similar effects as ACEI but tend to exert fewer undesired side effects. Data on ARB in children with chronic renal disease are still very scarce, but these substances offer an alternative for patients who cannot tolerate ACEI due to unwarranted side effects. Combination therapy with ARB plus ACEI may be more effective than either drug class alone. However, we will need the results of further long-term prospective clinical studies, as well as a better understanding of the role of the AT(2) receptor, before combination therapy can be widely recommended. A trial of ARB plus ACEI is justified in selected patients if blood pressure and/or proteinuria cannot adequately be lowered by ACEI or ARB alone.