STUDY DESIGN: The indications of the lumbosacral spinal fusion has been very controversial. The posterior lumbar interbody fusion has the popularity of the spinal fusion: coaption of large surface areas of cancellous bone without shear forces, anatomic restoration and maintenance of more normal dimensions of the joint space, total discectomy as preparation for the fusion, and the accomplishment of better neural decompression without creating instability of the spine. OBJECTIVES: To evaluate the long-term results of the surgical management of degenerative lumbar disease by the modified transdiscal posterior lumbar interbody fusion technique using cancellous chip graft were analyzed. SUMMARY OF LITERATURE REVIEW: The disadvantages of classical posterior lumbar interbody fusion has a injury of nerve root by extensive retraction with the insertion of peg grafts into the disc space, compression of root by graft retropulsion, inadeguate removal of annulus fibrosus and end plates from excessive bleeding from venous plexus of spinal canal and from vertebral cancellous bone. MATERIALS & METHOD: Author's 43 cases who had transpedicular instrumentation and modified transdiscal PLIF using cancellous chip graft since 1989 in the Department of Orthopedic Surgery, Korea University Hospital were analyzed, retrospectively. After preparation of the interspace has been complete by total discectomy, removal of the cartilaginous end plates and perforation of the cortical plates using the ring curette, cancellous chip grafts are inserted into the interspace with the Funnel technique. The structural success of each fusion was documented by sequencial radiographs. The criteria for fusion included: homogenous amalgamation of the fusion mass and vertebral bodies, trabeculation, mass configuration, and no motion demonstrable by hyperflexion studies. The results obtained were as follows: 1. Stable fusion was obtained in 39 patients(91%) at post-operative 6 months. 2. Clinically no patient developed neurologic deficit after fusion and 41 patients (95.3%) had good results by Gill's criteria. 3. No significant complications influencing operative result were observed except minor complications such as paralytic ileus, transient dysuria and superficial infection. 4. In conclusion, modified transdiscal PLIF procedure using cancellous chip graft showed excellent clinical and radiological results to achieve spinal fusion and the procedure is technically feasible and should be considered more widely employed.