One hundred forty patients with proved brucellosis and clinical evidence of bone and joint involvement were evaluated prospectively by 99mTc-methylene diphosphonate scintigraphy to assess the frequency of positive findings. To evaluate the radiographic abnormalities associated with positive scintigraphy, all areas of the skeleton that showed abnormal uptake were studied further by plain radiography. High-resolution CT was performed in all patients who had spinal lesions. Ninety-six patients (69%) had abnormal radionuclide uptake in 57 extraspinal and 101 spinal sites. Uptake was increased in 53 joints and three long bones and decreased in one joint. The knee was the most frequently involved site; the second was the sacroiliac joint. Radiographic and high-resolution CT changes were seen in only 12 (21%) of 57 extraspinal sites. In the spine, the abnormal scintigrams showed either focal increased uptake in affected vertebral bodies (detected mostly on the anterior view and seen in 51 lower thoracic and lumbar vertebrae in 24 patients) or diffuse increased uptake in adjacent vertebrae (detected in anterior and posterior views and seen in 50 different disk levels in 38 patients). Radiographic and high-resolution CT changes were seen at all scintigraphically positive sites. We conclude that bone scintigraphy is a useful method for screening patients with osteoarticular brucellosis. It is more sensitive than radiography in assessing involvement of the extraspinal skeleton and in the spine, it allows accurate localization of affected areas.