The aim of the study was to evaluate the effect of a reduction of the number of general practitioners on call on the use of ambulance emergency service. A prospective registration of all ambulance emergency activity in the county of Ringkøbing over an eight week period was made before and after the reduction of the number of general practitioners on call, together with a 4 + 4 week prospective registration of persons who claimed that contact to the general practitioners service was impossible, therefore resulting in a contact to the emergency central or the accident and emergency department. The numbers of emergency calls and emergency ambulance services in the population were unchanged, but there was a significant reduction from 78.9% to 69.3% in the relative number of ambulance services resulting in an admission to hospital of the patient. The number of patients, who claimed that contact to the general practitioner service was impossible was unchanged. We conclude that a reduction of the number of general practitioners on call has resulted in a reduction in the relative number of ambulance services resulting in hospital admission of the patient, which suggests a decline in the threshold of the population for calling an ambulance.