We explored whether the serum concentration of interleukin 6 (IL-6) is associated with matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in rheumatoid arthritis (RA) patients. Serum levels of IL-6, interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), gelatinase B (MMP-9), TIMP-1 and TIMP-2 were assessed with an ELISA technique in 30 RA patients. We observed the association between IL-6 and MMP-1 (p < 0.001), MMP-3 (p < 0.05), MMP-9 (p < 0.001), TIMP-1 (p < 0.01) and TIMP-2 (p < 0.05). Additionally, serum IL-6, measured MMPs and TIMP-1 correlated with the erythrocyte sedimentation rate, C reactive protein plasma level and the number of swollen joints. We suggest that assessing the serum IL-6, MMP-1, MMP-3, MMP-9 and TIMP-1 levels may be helpful in the prediction of the RA activity.