A search of the English-language medical literature found only two cases in which expansion of an osteochondroma into the lumbar spinal canal caused sciatica. We report another two cases of spinal nerve root compression by solitary lumbar spinal canal osteochondromas: in a 56-year-old man and a 55-year-old woman with no history of hereditary multiple exostoses. Osteochondromas compressing the spinal nerve root were seen at the inferior articular processes of the lumbar vertebrae by computed tomography (CT), three-dimensional reconstruction of CT scans, myelography, and magnetic resonance imaging. The symptoms disappeared after surgical removal of the lesions. Histopathologic examination confirmed the diagnosis of benign osteochondroma.