Our objective was to study the demographic characteristics of patients referred from general practitioners to a rheumatology outpatient clinic and to analyse the content and quality of the referral letters. During a 12-month period 346 randomly chosen referral letters of new patients from GPs to a rheumatology outpatient clinic were evaluated. The mean age of the 346 referred patients (73.1% females and 26.9% males) was 45.5 years and 17.8% were 60 or older. Mean disease duration at the time of referral was 50.9 months (1-432 months). Only about 10% of the patients referred had a disease duration of 1 month or less. The current clinical problem was appropriately presented in 95% of the referral letters. In only 0.9% of referrals had there been a prior phone consultation. Altogether, 95.1% of the referrals were as a result of diagnosis or treatment, and in nearly half the cases a diagnosis of inflammatory rheumatic disease was suggested. In 23% of the letters the result of clinical examinations were missing. Laboratory tests such as serum rheumatoid factor, antinuclear antibodies and HLA-B27 were used by GPs to screen for rheumatic disease in general. A lack of correlation between clinical manifestations and subsequently requested laboratory examinations was frequently found in the referral letters, exemplified by the use of HLA-B27 in rheumatoid arthritis and serum rheumatoid factors in ankylosing spondylitis. These results show that among GPs the threshold for referring patients to a rheumatology outpatient clinic appears rather high, and that patients are subjected to long observation periods before referral. A more frequent use of phone consultations and an improvement in the diagnostic skills of GPs may positively influence the selection of patients for referral and shorten the long waiting lists in rheumatology. This need for improvement was further strengthened by GPs' inappropriate use of laboratory tests.