The information content of early bone changes in computed tomography (CT) of pyogenic non-tuberculous spondylitis and spinal tuberculosis is analysed. The CT findings are compared with conventional x-ray images including tomography. In 3 of 16 patients no indications of osteomyelitis were found by conventional x-ray images, whereas CT revealed paravertebral soft tissue swelling or abscesses and osteolysis and thus established the diagnosis of spondylitis. In one patient the process caused neurologic symptoms by extending into the epidural space. The contributions of CT to the diagnosis of spondylitis are to delineate the extent of soft tissue swelling, to detect small defects in the vertebral bodies, to exclude disc involvement, and to differentiate inflammations and other destructive changes. CT can be used for fine needle localization and aspiration of tissue or pus for histological or bacteriological investigations to establish the pathological diagnosis.