Published data were reviewed to evaluate the occurrence of antiphospholipid antibodies (aPL) in rheumatoid arthritis (RA) patients and to investigate their clinical relevance in this population. The mean prevalence of aPL in RA patients was calculated at 28%. Few studies have found a relationship between aPL and thrombosis, particularly in combination with other risk factors. Conflicting results have been reported on the association of anticardiolipin antibodies (aCL) positivity and neurologic symptoms, Reynaoud's phenomenon, radiologic erosions, extra-articular RA manifestations, rheumatoid factor, and atherosclerosis. Some studies, however, suggest that there is a correlation present between those antibodies and C-reactive protein levels, rheumatoid factor (RF) and antinuclear antibodies. Tumor necrosis factor blocking agents may cause an induction of aCL, but it seems like they do not cause any clinical features related to the antiphospholipid syndrome.