We describe a 31-years-old female patient with severe pain in both knees who had been diagnosed as Behcet's disease (BD) for 12 years. She had had a history of complications due to BD including superior vena cava thrombosis, pulmonary thromboembolism, uveitis, and erythema nodosum and has reported the administration of corticosteroid therapy irregularly. After radiologic evaluation, she has been diagnosed with bone infarction of both left and right knee with the existance of lupus anticoagulants (LA) positivity. Severe joint pain without the evidence of arthritis must alert the clinician to the possibility of bone necrosis of the extremity, although those may rarely occur bilateral in BD.