An increased incidence of osteoarticular tuberculosis (TBC) has been reported during recent years. We report a case of TBC arthritis of the knee in which magnetic resonance tomography (MRI) provided images suggestive of this finding, in contrast to plain radiographs and joint sonography. The diagnosis was confirmed with culture for tuberculous bacilli. As far as we know, this is the first study comparing radiographs, joint sonography, and MRI.