The authors report our experience on 19 cases of discitis developed after operations for herniated lumbar disc. Because of the negativity of the neuroradiological studies in the acute stage, the recognition of the typical syndrome (severe back pain, spasm of the paravertebral lumbar muscles, limited spinal motility, fever) beginning 3-30 days post-operatively and the study of some laboratory tests (elevated Erythrocyte sedimentation rate (ESR) and midly to moderately elevated white blood cells (WBC) are very important for diagnosis. The first radiographic findings (disc space narrowing, ecc.) are detectable only 4 to 6 weeks after the first symptoms; other X-ray findings are not seen post-operatively before 6 months-2 years. The CT-scan is diagnostic of discitis only when the following three specific signs are present: a) anterior paravertebral soft tissue swelling with obliteration of paravertebral fat planes; b) fragmentation or erosion of vertebral end plates; c) paravertebral fluid collection (abscess). In our experience a period of immobilization of the spine with a plaster body jackets and the use of adequate antibiotic therapy are the more effective treatment. Undoubtedly the discits are the results of an infection that must be prevented adhering to the aseptic principles not only during surgery but also during the procedures performed in the radiology suite.