The variation in the number of patients general practitioners refer to hospital is a source of concern because of the costs generated and the implications for quality and quantity of care This paper compares 32 general practitioners with high referral rates with 35 doctors with low referral rates drawn from a study of 201 doctors. The mean referral rate for all 201 doctors was 6.6 per 100 consultations - for those with high referral rates the mean was 11.8 and for those with low referral rates 2.9. Differences between doctors with high and low referral rates with respect to age, sex, social class and diagnostic case mix of patients consulting were small. Doctors with high referral rates referred more patients in all categories. There were also few differences between the two groups with respect to the characteristics of the doctors themselves or their practices. The findings are discussed in the context of proposals to provide general practitioners with information on their own referral rates compared with those of other doctors.