Besides defining the appropriate doses of frusemide in uraemic patients, A. Heidland's contribution to the treatment of hypertension in chronic renal failure consisted in the following demonstrations: (1) In patients on chronic haemodialysis, calcium antagonists have a beneficial effect on their glucose intolerance and decreased plasma levels of 25OH vitamin D while their effect on blood lipids is neutral. (2) In 5/6 nephrectomized rats, captopril, verapamil, and metoprolol have the same protective effect on their GFR and tubular secretion of protons, at equal blood-pressure-lowering effect. (3) In rats with streptozotocin-induced diabetes, atrial natriuretic peptide does not play a role in their hyperfiltration. (4) Severe retinopathy is observed in patients with uraemic nephropathies at a much smaller elevation of their blood pressure than in patients with essential hypertension. This article reviews the following points: (1) The role of hypertension in the loss of renal function is convincingly demonstrated only in a few experimental models, and in man only in malignant hypertension and diabetic nephropathy but not in essential hypertension nor in non-diabetic nephropathy. However, preliminary results suggests that antihypertensive treatment may retard the progression of renal disease in normotensive patients (DBP <90 mmHg) with either microalbuminuric diabetes and normal renal function or non-diabetic uraemic nephropathy. (2) Only the ACE inhibitors have been proved to have a specific renal protective effect, independent of their diurnal blood-pressure-lowering effect, both in diabetic nephropathy and in non-diabetic uraemic nephropathy.