The choice of drugs to initiate therapy for the management of hypertension remains contentious and diuretics are central to this controversy. Because most of the major trials involve complex treatment algorithms and allow diverse background treatments, one of the greatest challenges lies in separating out true class-specific effects - for example, separating true class-specific effects of diuretics from those of beta blockers. Despite these difficulties, the evidence confirms that diuretics are at least as effective as the newer first line groups in preventing cardiovascular events. The main area of doubt lies in relation to the risk of renal outcomes and of metabolic outcomes, such as new onset diabetes - where the evidence suggests that drugs that inhibit the renin-angiotensin system may be more protective than all other drug classes. These issues are reflected in the most recent international guidelines, all of which include diuretics among the first-line drugs for the treatment of hypertension, although they do differ on the role of diuretics in the initiation of therapy. Diuretics remain important for treating hypertension, especially in combination with other drug classes. The particular place of diuretics in the rank order of drugs must be tailored to suit the clinical situation in the individual patient. This will vary from a preferred option, as in black patients or elderly patients with systolic hypertension, to a second-line option in patients at high risk of developing new onset diabetes.