No legislation exists about ambulance services in Denmark. The present Danish prehospital treatment is undertaken by Falcks Redningskorps A/S and the municipal fire services. During a period of 12 months (1.2.1988-31.1.1989) a prospective investigation was carried out in Odense concerning the effect of medical support to the ambulance service, partly in the form of a medically staffed ambulance, partly in the form of an arrangement in which an independent doctor's car (rendez-vous arrangement) was sent together with the nearest ambulance. In addition, the heart ambulance model as recommended by the Danish National Board of Health was also tested. Experience from abroad and recent Danish trial arrangements demonstrate the positive effect of extended professional prehospital treatment. The authors consider, therefore, that an ambulance law is required as this would ensure better and more uniform prehospital treatment in Denmark. Planning of the future prehospital treatment of acute and injured patients including the extent of the training, equipment and treatment must be established on the basis of a healtheconomical assessment of the Danish arrangements.