Osteoid osteomas, relatively rare lesions in the upper extremity, can be a persistent source of hand or wrist pain. Patients under age 40 who have otherwise unexplained pain should be evaluated. Relief of pain with oral nonsteroidal anti-inflammatory drugs should suggest the possibility of osteoid osteoma. Examination may demonstrate localized swelling or joint effusion. Radiographs should be examined for sclerosis in the region of pain. If radiographs are nondiagnostic, a bone scan should be obtained. If the nidus cannot be clearly visualized by radiography and bone scan, a CT scan should be obtained. If the location of the nidus makes excision difficult without removal of a large block of bone, localization with a CT-guided needle or by radioisotope labeling will help to assure removal of the nidus.