PURPOSE: To assess the value of 3D CISS (constructive interference in steady state) MR sequence in imaging the cervical spine. MATERIALS AND METHODS: MR images of cervical spine were prospectively obtained with both conventional (sagittal TSE and axial 2D FLASH) and CISS sequences in 20 patients suspected of having cervical spinal diseases. MR technique was performed on a 1.5T MR machine. Axial, oblique coronal, and curved coronal images were reformatted with the 3D raw datas of CISS sequence which were obtained in cornal plane. The findings of CISS sequence were compared with those of the conventional sequence in terms of visualization of the neural foramen and nerve roots, detection and differentiation of herniated disc, conspicuity of the intramedullary lesion, contrast between the CSF and spinal cord and between the gray and white matters within the cord. RESULTS: In 17 cases including traumatic root avulsions, 3D CISS sequence demonstrated the intradural nerve roots with excellent contrast especially in coronal plane. Reformatted oblique coronal images of CISS sequence offered better visualization of entire neural foramen beyond the region of interest. CISS sequence was superior to the conventional sequence in demonstration of disease extent and correlation to the clinical symptoms in 4.5 cases of foraminal stenosis and in contrast between the CSF and spinal cord (n=15). CISS sequence was almost equal to the conventional sequence in detection of herniated disc (n=15). CISS was inferior to the conventional sequence in differentiation of herniated disc (n=7), delineation of intramedullary lesion (n=4) and in contrast between the gray and white matter within the cord in all patients. CONCLUSION: The 3D CISS sequence gives better information than the conventional sequence especially in the evaluation of the nerve roots and neural foramens but worse contrast of intramedullary lesion. It may well be used as a supplementary sequence in assessment of foraminal stenosis and nerve root injury.