The study will be a prospective, cross over, randomized trial. All patients fulfilling the inclusion and exclusion criteria, after a short screening period, will be treated with aliskiren or losartan. After a washout period of 2 weeks a cross over will be made between the two groups. Aliskiren will be given in a preliminary dosage of 150 mg per day, after a follow up of two weeks dosage will be increased to 300 mg per day. Losartan will be given in a preliminary dosage of 50 mg per day and after a two weeks follow up dosage will be increased to 100 mg per day. Two weeks after initiation of each treatment potassium and creatinin levels will be assessed. The follow up will be conducted in the Research and Development unit in Assaf Harofeh Medical Center at 0, 3 and 6 months and after the wash out period. On each visit patients BP will be assessed by 24 ambulatory BP monitoring. Blood will be drawn (10 cc) for Hemoglobin levels, electrolytes, renal and liver functions, total cholesterol, high density lipoprotein-cholesterol (HDL- cholesterol), triglycerides (TG), oxidized low density lipoprotein (ox-LDL) and hs- CRP. LDL-cholesterol will be calculated. PRA will be measured by radioimmunoassay of generated AI, PRC and plasma aldosterone will be measured by immunochemiluminescence. In addition NO and isoprostane will be measured as an index to oxidative stress. Platelet function and arterial stiffness will be assessed. The patients' medication regimen will not be changed throughout the study period.