OBJECTIVE: This study is based on the Danish DANBIO and the Norwegian NOR-DMARD databases. It was undertaken to investigate changes in prescription practice during the first three years of post-marketing use of biological drugs, and to find the proportion of patients who would not have received TNF-blocking agents if the prescription guidelines of the United Kingdom (UK) and Holland were applied. METHODS: Rheumatoid arthritis (RA) patients receiving TNF-blocking agents from Denmark (n= 823, age: 55.2 yrs, 72.2% women) and Norway (n= 371, age: 51.8 yrs, 75.4% women) were registered from 2000 to 2003 and each year was analysed separately. Prescription guidelines in the UK (minimum 2 previous Disease Modifying Anti-Rheumatic Drugs (DMARDs) and 28 joint Disease Activity Score (DAS28) >5.1) and Holland (minimum 1 previous DMARD and DAS28 >3.2) were applied to the data. RESULTS: Baseline disease activity and number of previous DMARDs declined significantly during the three years, e.g. baseline DAS28 decreased from 5.6 to 5.1 in both Denmark (p< 0.001) and Norway (p=0.004). 47.9 and 41.3% of the Norwegian and Danish patients, respectively, did not meet the UK-criteria for using TNF- blocking agents, and 10.5% and 5.7% did not meet the Dutch criteria. CONCLUSION: The Danish and Norwegian prescription practices of biological therapies in RA were similar, and became less stringent from 2000 to 2003. Prescriptions agreed well with the Dutch guidelines, while almost half of the patients did not meet the UK guidelines. This finding highlights that access to recent, effective therapies may vary across Europe.