The aim of the study was to evaluate the prevalence and diagnostic significance of anti-cyclic citrullinated peptide antibodies (anti-CCP) and IgM-RF in rheumatoid arthritis patients. A total of 173 RA patients [fulfilling the ARA 1987 diagnostic criteria; 82.1% female; median age 51.5 yrs (20-80); median symptoms duration 12 months (1.5-408)] were included in the study. The second generation enzyme-linked immunosorbent assay (ELISA) kit was used for the detection of anti-CCP. Two classical tests, Waaler-Rose and latex fixation test, were performed to determine the presence and titer of IgM-RF. Anti-CCP2 demonstrated significantly higher sensitivity (88.4%) in comparison to IgM-RF (46.8%). In 81.5% of IgM-RF-negative patients the presence of anti-CCP2 was found. The subgroup of IgM-RF-positive and aCCP2-negative patients formed a considerable minority, while in most cases aCCP2 antibodies were observed, and in much greater amounts than their cut-off value. Additionally, a significant association between serum aCCP2 and IgM-RF positivity, as well as between the aCCP2 value and IgM-RF titer in the Lx method, was demonstrated. Second generation ELISA detection of antibodies to cyclic citrullinated peptide showed higher diagnostic performance for RA in terms of sensitivity than tests used for detection of RF.