OBJECTIVE To evaluate the serum concentration of the mature, crosslinked carboxy terminal telopeptide of type I collagen (ICTP) in patients with early onset rheumatoid arthritis (RA) and to assess its correlation with clinically relevant features of the disease. METHODS The serum ICTP concentration was measured in 99 adult patients with RA with a duration of disease less than one year. The main clinical outcome measures were joint count, modified Lansbury index, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Larsen index and number of erosions in peripheral joints. RESULTS There was a strong positive correlation (p < 0.001) between the serum ICTP concentration and the Lansbury joint index and a weaker but still significant correlation (p < 0.01) between the serum ICTP concentration and the number of eroded hand and foot joints. CONCLUSIONS Serum ICTP may have value as a marker of tissue destruction in patients with early RA.