Blockade of the renin-angiotensin system has proved an important principle in the pharmacotherapy of cardiovascular diseases. There is now overwhelming documentation on the beneficial effect of angiotensin converting enzyme inhibitors (ACE inhibitors) on mortality and morbidity in patients with cardiovascular risk factors. Such documentation is still lacking for the angiotensin II receptor antagonists which, in 1999, sold for 77% of the amount spent on ACE inhibitors in Denmark. This review assesses the therapeutic effects of angiotensin II antagonists compared with the ACE inhibitors in patients with uncomplicated essential hypertension. From 21 comparative studies with a duration of up to one year, it can be concluded that the lowering of the blood pressure with the two classes is similar. Both showed relatively few side effects, the only difference being a higher incidence of cough after ACE inhibitors. Until larger comparative long-term studies on mortality and morbidity have been conducted, angiotensin II antagonists should only be used in hypertensive patients experiencing unacceptable side effects with ACE inhibitors.