Primary subacute osteomyelitis is an infection of the bone that continues for several weeks without any acute infectious manifestations such as fever, local pain and swelling. A diagnosis is often delayed because of the slow onset, the subtle radiological changes and the absence of infectious clinical and laboratory manifestations. Primary subacute osteomyelitis in 35% of primary osteomyelitis cases, almost developed in the metaphysis, but there is no report of subacute epiphyseal osteomyelitis in Korea. We report a case of primary subacute epiphyseal osteomyelitis in the distal femur which was treated conservatively with a satisfactory outcome.