Lumbar spinal stenosis (LSS) is a disabling condition associated with the narrowing of the spinal canal or vertebral foramina at one or several levels of the lumbar spine. Typical symptoms of LSS include low back pain (LBP), leg pain, weakness, and pseudo-claudication, all of which can markedly reduce function and activity levels. Low back pain is one of the commonest symptoms for which patients seek medical consultation. Paraspinal muscles play an important role in the stability and functional movement of the lumbar vertebral column.However, our understanding of their contribution to low back pain and disability is unclear. Systematic reviews have reported conflicting evidence for an association between paraspinal muscle size and low back pain and a paucity of data examining muscle cross-sectional area (CSA) and low back disability. Adult patients of either sex with low back pain due to degenerative lumbar spinal stenosis with or without neurological deficits visiting or admitted to our hospital from February 2021 to October 2022 were taken into the study. A total of 40 patients are included in this cross-sectional study. Patients were divided into two groups according to their ODI score (≤42 = moderate disability, >42 = severe disability), to compare the means for the different clinical characteristics and muscle parameters between the groups. Quantitative measurements of multifidus, erector spinae, and psoas muscles were obtained from the 1.5 Tesla MRI machine. All muscle measurements were taken bilaterally at the level of the superior endplate of the L5 vertebra and the inferior endplate of the L5 vertebra. The comparison of muscle parameters done between patients with moderate disability and severe disability showed statistically significant greater Multifidus muscle atrophy and fat infiltration both at the superior and inferior endplate of L5.