Educational Objectives As a result of reading this article, physicians should be able to: 1. Discuss the clinical presentation of and different imaging modality options for suspected osteoid osteomas. 2. Develop an insight into the histopathology and histochemistry of osteoid osteomas. 3. Use diagnostic processes in the differential diagnosis of suspected osteoid osteomas. 4. Apply current treatment depending on the location and accessibility of the lesion. Osteoid osteoma is the third most common benign bone tumor. The authors describe the clinical presentation, diagnostic investigations, differential diagnosis, histopathology, and treatment options for this condition, including a comprehensive review of the literature. Osteoid osteomas have wide variations in presentation and tend to present in the second decade of life, with pain that is worse at night and is relieved by salicylates. Plain radiographs and computed tomography scans are the mainstay of imaging; however, bone scintigraphy, single-photon emission computed tomography, magnetic resonance imaging, and sonography are also used. Osteoid osteomas consist of a nidus with surrounding sclerotic bone. The differential diagnosis covers a wide range of conditions due to the variable presentation of osteoid osteoma. The natural history is for regression to occur within 6 to 15 years with no treatment; however, this can be reduced to 2 to 3 years with the use of aspirin and non-steroidal anti-inflammatory drugs. Computed tomography–guided percutaneous techniques, including trephine excision, cryoablation, radiofrequency ablation, and laser thermocoagulation, are described.