Lipoma arborescens is a rare intra articular lesion consisting of a villous lipomatous proliferation of the synovial lining and occurs mainly in the knee joint. It is mostly found in older patients with joint trauma, meniscal lesions or chronic synovitis. The authors describe one case of a 29-year-old male with multiple lipomas in the right knee joint who has a history of joint trauma. He had joint effusion, pain, giving way and restricted terminal extension of the right knee. Histology and gross findings are consistent with the lipoma arborescens. After arthroscopic excision of the masses, symptom was relieved completely and the patient had gained full range of motion of the right knee joint.