Thiazide-type diuretics are widely used in the treatment of hypertension worldwide. This class of drugs have major intraclass pharmacokinetic variety and efficency, with one type appearing to be better than the others. Chlorthalidone, showing to be the most effective and possible the best drug, is not available in Norway. From 2004, prescription of thiazide-type diuretics as a first choice in patients with uncomplicated hypertension have been mandatory in Norway. This has sparked great debate in the Norwegian medical community where many have been reluctant to uncritical and widespread use of these drugs. Huge and expensive clinical trials, though not perfectly executed, have proven the safety and efficiency of the drugs, but with mechanisms of action not fully understood,and with clinical trials not directly applicable to the Norwegian population many are still skeptical. Supporters and critics in this dispute have presented valid arguments.Conclusion: Thiazide-type diuretics administred in small concentrations have been proven to cause only minimal disturbances in biochemical parameters and should be used either in low dose monotherapy or in low dose combination therapy, the latter being themore beneficial of the two for the patient.