Spinal osteoid osteomas are rare. We report 21 cases, that have been studied and treated since 1985. The tumor affects young people, who are less than 25 years old. The pain is the most common sign. Diagnosis is difficult, but can be made by radiology. X ray sometimes enables to suspect the diagnosis. Scintigraphy shows a focus hyperfixation more suggestive. Computed tomography enables the diagnosis by showing a bony lacuna surrounded by osteosclerosis. Moreover, computed tomography localizes very well the nidus of the osteoid osteoma, and guides the surgical treatment. Since computed tomography, other techniques like angiography and tomography are less used for diagnosis.