Anticyclic citrullinated peptide antibodies (anti-CCP) have been described almost exclusively in patients with rheumatoid arthritis. Recently, these autoantibodies have been found in patients with active tuberculosis. Leprosy is another mycobacterial disease where the presence of autoantibodies has been described by several authors. In this study, 64 patients with leprosy (32 paucibacillary and 32 multibacillary forms of the disease) were evaluated and only 2 patients were positive for the presence of anti-CCP. The low frequency of anti-CCP in leprosy sera demonstrated in our study illustrates the high specificity of anti-CCP for the diagnosis of rheumatoid arthritis.