The early diagnosis of rheumatoid arthritis (RA) has become a priority owing to the availability of effective disease-modifying agents that can improve patient wellbeing and influence the clinical outcome. However, this represents a real challenge, as no clinical, radiological or immunological features are pathognomonic at the time of presentation. For this reason, development of the anti-cyclic citrullinated peptide (CCP) antibody assay, a highly disease-specific serological marker for RA, has been a great step forward for the rheumatologist and the clinical laboratory. Over recent years, this test has increased in popularity and many studies have been performed. This review briefly considers the most recent data on the diagnostic accuracy of the CCP test, the genetic background that predisposes to antibody production, the diagnostic, prognostic and predictive values, and the clinical use of the assay in patients with RA.