Objective To describe changes between 1992 and 2003 in age, sex, factors at resuscitation and survival among patients suffering from out-of-hospital cardiac arrest in Sweden. Methods This was a prospective observational study including various ambulance organizations in Sweden. Patients suffering from out-of-hospital cardiac arrest between 1992 and 2003 included in the Swedish Cardiac Arrest Registry were followed for survival to 1 month. Results In all 19 791 cases took part in the survey. There was a slight increase in mean age from 68 to 70 years (P=0.025) and an increase of females from 29 to 32% (P=0.0001). There was a change in witnessed status (P<0.0001) with an increase in crew-witnessed cases and a decrease in non-witnessed cases. There was a decrease in cases of a cardiac etiology from 75 to 61% (P<0.0001) and a decrease in the percentage found in ventricular fibrillation from 36 to 25% (P<0.0001). When crew-witnessed cases were excluded the proportion receiving bystander cardiopulmonary resuscitation (CPR) increased from 30 to 42% (P<0.0001). There was a slight increase in the overall proportion of patients hospitalized alive from 16 to 20% (P=0.032). There was no significant change in the overall proportion of survivors at 1 month after cardiac arrest (4.5% in 1992 and 5.0% in 2003). Conclusions Among patients suffering from out-of-hospital cardiac arrest in Sweden some changes took place. The most important ones were a decrease in the proportion of patients found in ventricular fibrillation and an increase in the proportion of patients receiving bystander CPR. The proportion of patients admitted alive to hospital increased moderately, whereas the proportion of patients alive after 1 month remained unchanged.