Hypertension and diabetes mellitus are interrelated diseases that, if untreated, strongly predispose to atherosclerotic cardiovascular disease and renal disease. More than 3 million Americans have both hypertension and diabetes, which are particularly prevalent in the socioeconomically disadvantaged. Hypertension contributes substantially to morbidity and mortality in people with diabetes. This report is an update of the 1987 working group report on hypertension and diabetes and includes important new information on the management of hypertension in people with diabetes. Although treatment of hypertension in most people with diabetes does not differ from that in people who do not have diabetes, this report outlines some special considerations relevant to the presence of both diseases. Lifestyle modification is considered as an initial treatment modality or as an adjunct to pharmacologic measures. This report also includes a discussion of the treatment of hypertension and diabetes in children, an expanded review of sexual dysfunction, and an increased emphasis on the effect of hypertension and diabetes on target organs. A treatment algorithm represents a practical guideline for the physician. Since the previous report, there has been an increased awareness, through clinical trials and pharmacologic research, of the importance of flexibility in the use of antihypertensive drugs as well as a refinement of nonpharmacologic approaches in treating people with both hypertension and diabetes.