The voluntary Swedish Cardiac Arrest Registry has collected and analyzed 14,065 standardised reports on cardiac arrests up until May 1995. The reports have been collected from approximately half of Sweden's ambulance districts, which cover 60% of the population. Resuscitation was attempted in 10,966 cases. The median age was 70 years. In 70.0% the arrest was witnessed, and in 43.3% the first recorded rhythm was VT/VF. Bystander-CPR was initiated in 32.3% of the cases. Most cardiac arrests took place at home (65.8%) and 67.1% were judged to be of cardiac origin. In 1692 cases (15.4%), the patient was admitted alive in hospital and 544 patients (5.0%) were alive after 1 month. Survival to 1 month in the subgroup which presented with VT/VF was 9.5%. We found no significant difference between survival in large cities and smaller communities. The survivors were analysed in relation to time to defibrillation and we found a strong correlation between a short time and increased survival.