To elucidate the reasons for delay in the diagnosis of spinal cord tumors despite the availability of MRI in Japan, we reviewed the clinical records of 60 patients with tumors with reference to histological diagnosis, initial symptoms, time interval between onset of the initial symptoms and the first visit to a physician, and the subsequent interval to diagnosis using MRI. The intervals from onset of the initial symptoms to diagnosis using MRI for cervical, thoracic, and lumbar tumors were 16.9, 16.8 and 8.1 months, respectively. Of the 20 patients with thoracic spine tumors, 10 had been examined with MRI at an incorrect level. The patients with cervical tumors tended to have delayed diagnoses due to the time taken before visiting a physician. Tumors in the thoracic spine were missed because the symptoms were similar to more common degenerative lumbar disorders and the absence of proper MRI screening. The possibility of thoracic spinal tumor should be kept in mind when unexplained low back pain persists in response to various treatments.