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Laminoplasty of the cervical spine was performed by sagittal splitting of spinous processes in 127 cases, 63 males and 64 females with cervical myelopathy. The iliac bone was grafted into split spinous processes in 63 cases, and their average age was 59.1 years. The bone was inserted into each split spinous process of 46 cases (K-O method), and a longer bone was inserted to obtain interspinous fusion in 17 cases (K-PF method). No bone was grafted in split spinous process of 64 cases (T-method), and their average age was 61.6 years. Operative time was shorter and blood loss was less in cases without bone grafting than with bone grafting. There was no significant difference between K-O, K-PF and T-method with regard to pre- and postoperative JOA score, and Hirabayashi's recovery rate. Alignment of the cervical spine of lateral view X-ray at neutral position was evaluated before and after surgery in 39 cases by K-O method, 17 cases by K-PF method and 53 cases by T-method. In 31 cases by K-O method with preoperative lordosis, 25 remained lordotic, 3 were straight and 3 were kyphotic, postoperatively. In 17 cases by K-PF method, 10 cases with preoperative lordosis maintained all to have lordosis. Bone grafting may maintain lordosis of the cervical spine. In the patients without bone grafting by T-method, 44 out of 46 with preoperative lordosis remained lordotic, but 2 became straight. A trend of improvement was shown more in cases with lordosis than with straight or kyphotic spine by Hirabayashi's recovery rate. The range of motion of cervical spine was significantly decreased postoperatively in all three methods, more in cases with bone grafting. There was no significant difference of the angle of enlarged laminae, assessed by computed tomography, between right after surgery and at the time of follow-up, even though bone union did not occur or even the grafted bone became smaller or disappeared. The effect of laminoplasty was obtained whether or not bone grafting were p