Background: Of the various surgical modalities for treating spondylolysis and spondylolisthesis, transforaminal lumbar interbody fusion (TLIF) is considered the best. Objective: To assess the functional outcome in symptomatic lumbar spondylolisthesis and spondylolysis patients treated by TLIF using transpedicle screws and rods in terms of complications, changes in Visual Analog Score (VAS) and Oswestry disability index (ODI) among them. Methods: 20 patients (09 male, 11 female) admitted with isolated symptomatic lumbar spondylolisthesis of any grade with or without spinal canal stenosis, treated with Transforaminal Lumbar interbody fusion were included in the study. Results: Most commonly affected age group was 40–50 years, degenerative type of spondylolisthesis is more common than isthmic and traumatic types of spondylolisthesis. The mean of disc height was 8.96 mm pre–operatively and 10.69 mm postoperatively. Mean Visual analog score (VAS) for Leg pain pre–operatively was 7.50 ± 1.05, with the post–operative VAS being 2.20 ± 1.19. Pre–operative ODI score was 59.11 ± 8.65, and post–operative ODI score was 39.10 ± 9.69. In situ transforaminal lumbar interbody fusion and posterior decompression significantly reduced the pain and functional disability in patients. Conclusion: Transforaminal lumbar interbody fusion with transpedicular screws along with posterior decompression is safe and effective in achieving good functional outcome. It provides better functional outcome by providing pain relief and improving quality of life in the patients.