In the absence of randomized control data, the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommended that patients with diabetes mellitus should have their blood pressure decreased to less than 130/80 mm Hg. In the absence of randomized control data, the American Diabetes Association recommended that patients with diabetes mellitus and hypertension should have their blood pressure decreased to less than 130/80 mm Hg. In the absence of randomized control data, the American Heart Association 2007 guidelines recommended that patients with diabetes mellitus and hypertension should have their blood pressure decreased to less than 130/80 mm Hg. The 2009 European Society of Hypertension guidelines stated that lowering the blood pressure to less than 130/80 mm Hg in patients with diabetes mellitus is unsupported by prospective trial data, and that the systolic blood pressure should be reduced to less than 140 mm Hg in these patients. The American College of Cardiology Foundation/ American Heart Association 2011 expert consensus document on hypertension in the elderly recommended that the blood pressure should be decreased to less than 140/90 mm Hg in adults younger than 80 years with diabetes mellitus or chronic kidney disease. On the basis of data from the Hypertension in the Very Elderly trial, these guidelines recommended that the systolic blood pressure should be reduced to 140 to 145 mm Hg if tolerated in adults aged 80 years and older. I concur with these guidelines. The following studies discuss the reasons for my recommendations.