Abstract Background: Lumbosacral fixation is a common surgical procedure for various indications including spondylolithesis with neurogenic claudication pain secondary to degenerative spinal canal stenosis. Segment failure following lumbosacral fixation is a serious complication resulting from spondylolith-esis above or below fixed vertebrae. Segment failure is an important cause of recurrence of symptoms and/or appearance of new symptoms. This complication must be properly diag-nosed and managed to improve short and long term surgery outcome. Aim of Study: This study aimed to assess the management of segment failure post lumbar fixation by one level extension of fixation. Patients and Methods: This study included 15 patients presenting with segment failure post lumbar fixation. Inclusion criteria was improvement of pain and/or neurologic claudica-tion after initial lumbar fixation. The occurrence of segment failure was documented by lumbosacral magnetic resonance imaging MRI. All patients were managed by one level exten-sion of fixation. Results: Patients were five (33.3%) females and ten (66.6%) males with an age that ranged from 33 to 67 years, mean age was 48±5.8 years. Body mass index BMI ranged from 23.6 to 35.7 with a mean of 31.4±3.7kg/m2. All patients were complaining from low back pain LBP, had radicular pain and presented with neurologic claudication. The duration between the initial lumbosacral fixation surgery and the operation for extension of fixation ranged from 1.7 to 3.1 years with a mean of 2.5±1.7 years. Conclusion: Segment failure is an importantcause of recurrence of symptoms after primary relief following lumbar fusion surgery. One level extension of fixation is a good option for management of segment failure post lumbar fixation.