The Danish Pacemaker Register was established in 1982 and since then all Danish pacemaker and lead implantations have been registered on a prospective basis by use of the European Pacemaker Patient Identification Card. The Register contains data on 17,002 patients with an implanted pacemaker. In 1994 the implantation rate was 314 per million inhabitants. The ECG indication was atrioventricular conduction disturbances in 46%, sick sinus syndrome in 37% and atrial fibrillation with bradycardia in 13%. Fifteen percent received a single atrial system and 41%, a dual chamber system. In 62% a rate adaptive pacemaker was used. Overall, the international recommendations for choice of pacing mode were met in 64% of the implantations. As the 11 implanting centres in Denmark report to the Register with a few days delay from the intervention, the Register is able to detect any irregularity in pacemaker or lead function within a very short period of time.