Thermographic findings in 10 cases of syringomyelia were reported. 7 cases were associated with Arnold-Chiari malformation and 3 cases with spinal adhesive arachnoiditis. The cases included 3 men and 7 women, aged 7 to 56 years (mean age 27.7 years). Comparing the right side of the body with the left side, in 9 cases, thermography demonstrated asymmetric skin temperature of the trunk or extremities. MRI revealed laterality of the syrinx at the level of cervical or lumbo-sacral cord in 9 cases. The side with the lower temperature corresponded with the side of lateralized syrinx in 8 cases. Neurologically, 9 cases had laterality of sensory disturbance and 6 cases had asymmetric motor weakness. The side with the lower temperature also corresponded with the laterality of sensory disturbance in 8 cases, and the side of the motor weakness in 4 cases. Considering these findings, many of the patients with syringomyelia are thought to have asymmetric skin temperature. Intramedullary involvement of sympathetic pathway by the syrinx may cause such a change. As thermography is non-invasive and easy to carry out, it should be a useful method for estimating or even detecting cases of syringomyelia, especially when applied to out-patients.