Abstract: Rheumatoid arthritis is a common disease occurring in 1% of the population. Therefore it is not unusual to see a rheumatoid arthritis patient who needs anticoagulation therapy for another reason than her or his RA. Anticoagulation therapy has no contra-indication for RA itself. However many drugs used in RA may interfere with anticoagulant drugs. The major problem arises from NSAIDs, particularly salicylate. These drugs have a synergistic effect on coumadin and related drugs. Two situations will occur in these patients: 1- The patient is taking NSAID and an anticoagulant must be given: This is the easiest event to manage. It will suffice to start with a lower dosage than in a normal situation. Depending on the reaction of the patient the dose will be adjusted. When the required dose of coumadin is found It is important to warn the patient not to change the dose of NSAID as this will effect the level of the obtained anticoagulation. 2- The patient is under anticoagulant and an NSAID is to be started. This is the more difficult situation because it is impossible to predict the degree of synergistic effect between the 2 drugs. It is preferable to reduce the coumadin dose while starting the NSAID, and then to adjust the coumadin dose as required. Anticoagulation may exceptionally be used for rheumatoid arthritis itself, in vasculitis complications such as mesenteric arteritis. Rheumatoid arthritis is not associated with coagulation disorders. However few cases are reported in the literature having different coagulation disorders: 1- Hypercoagulability with recurrent venous thrombosis cured after successful management of the RA. 2- Carotid artery thrombosis. 3- Anti factor V acquired circulating anticoagulant. 4- Anti factor VIII lupus anticoagulant. 5- Anticardiolipin antibodies (ACL) is not usually found in RA patients. However a study published by Keane and colleagues in 1987 in the British journal of Rheumatology reports ACL in 49% of patients. ACL was associated with the male sex and extra-articuiar manifestations.