To examine hospital referral rates in Finnish health centres according to doctors' and health centres characteristics. Survey of all general practice hospital referrals over one week. Central and northern part of Finland, in a region comprising 72% of the area of the country and one-third of the population. 851 health centre doctors. Referral rates in terms of characteristics of doctors and health centres. During the study period, the 851 health centre doctors had 58 760 consultations (mean 69 patients/week), and 2 921 (5%) patients were referred to secondary care. The variation between the highest and lowest referral quintile of the doctors was almost 17-fold, and of the health centres 2.4-fold. Relatively more referrals were made by locums, young, not yet graduated and female doctors than by specialized, more experienced and male doctors. A low referral rate is closely connetected with the extent of the general practitioners' professional experience and specialist training. Investing in specialist training and continuing medical education seems to be the best way to reduce high referral rates.