This study assesses how the use of hospitals is affected by GPs being given an opportunity to send their patients to private specialists for consultation instead of referring them exclusively to hospital outpatient clinics. In the City of Turku three populations were served for a period of over 34 months by different service models. The first model was implemented in municipal health centres by 10 GPs with a list system and an option to consult private specialists. In the second model there were four GPs in municipal health centres without a list system or the consultation option. The third model comprised four private GPs with a list system and the consultation option. Persons with private GPs with a list system had fewer visits to the hospital outpatient clinics and fewer bed days than persons served by a municipal GP, either with or without a list system. When GP's have the opportunity to send patients for consultation to private specialists, both the number of visits to hospital outpatient clinics and the number of bed days are reduced.