OBJECTIVES: Analysis of Rheumatoid Arthritis (RA) treatment patterns and associated health care resource use in patients treated unsuccessfully with at least two DMARDs (including metotrexate) in order to evaluate the costs of RA treatment. METHODS: Multi-center, non-interventional, retrospective study of 154 patients with rheumatoid arthritis diagnosed in accordance with the revised criteria of the American Rheumatism Association (1987). DAS 28 score ≥ 3.2 and prior inadequate response to at least two DMARDs (including MTX). Data on RA treatment patterns and associated health care resource use at different levels of disease activity were collected between 2004 and 2007. Costs of hospitalizations, visits at outpatient clinics, outpatient pharmacological treatment, therapeutic rehabilitation, during the first 6 months of the study for each patient were taken into account. RESULTS: Median total cost in first 6 months of observation period was 1203.45 PLN/patient/month (€356). Hospitalization related cost was 661.52 PLN/patient/month (€195,7), ambulatory treatment cost 415.70 PLN/patient/month (123€). Total and hospital costs were significantly negatively correlated with patients’ age (Spearman’s rho = -0.186 and -0.218, respectively). Higher DAS 28 score significantly increased total, hospital and ambulatory costs (Spearman’s rho = 0.362, 0.210 and 0.190, respectively). There was a tendency toward cost reduction with absence of concomitant diseases, university degree of patient and earlier calendar year of start of the treatment, especially after exclusion of DMARDS. CONCLUSIONS: Rheumatoid arthritis cost studies should take into account local factors influencing treatment patterns (like patient’s age) in evaluation of costs of RA treatment.