Hypertension and diabetes mellitus are a malignant combination of diseases for the kidney. They markedly increase the risk for progressive renal injury and are the largest single cause of renal failure. Strategies to reduce the risk for renal injury in hypertensive diabetics are very important. Although Type I and Type II diabetes are different diseases, they may be associated with similar mechanisms of renal injury in hypertensive patients. Reduction of elevated systemic arterial pressure is of proven benefit in limiting progressive renal injury in diabetic hypertensives. However, converting enzyme inhibitors and possibly the nondihydropyridine calcium antagonists may possess antiproteinuric abilities independent of blood pressure reduction which, in addition to their antihypertensive effects, may be important in limiting the progression of human diabetic renal disease. Long-term clinical trials have evaluated the impact of these and other agents on progression of diabetic renal disease. This paper reviews these trials and focuses on renal effects of antihypertensive agents independent of blood pressure reduction.