Background: Lumbar disc herniation (LDH) is one of the leading causes of lower back pain and disability, significantly impacting public health and socio-economic well-being. International studies have shown that paraspinal muscle size and structure correlate with age, body mass index (BMI), and spinal disorders. However, comprehensive MRI-based research investigating the correlation between LDH and specific morphometric parameters in Mongolia remains limited. Aim: To evaluate lumbar disc herniation using magnetic resonance imaging (MRI) and compare paraspinal muscle volume and subcutaneous fat thickness. Materials and Methods: An observational retrospective study design was conducted between June 2024 and June 2025 at Asraltmed and Orgil hospitals, enrolling 300 cases selected from 2,840 lumbar spine MRI scans based on inclusion and exclusion criteria. Demographic data (age, sex, BMI) were collected alongside MRI metrics. LDH type, size, location, and severity were evaluated using axial, sagittal, and coronal views across T1WI, T2WI, and STIR/T2FS sequences. Paraspinal muscle cross-sectional area (Multifidus, Erector spinae, Psoas) was measured on axial T1WI and T2WI sequences, while subcutaneous fat thickness was measured on sagittal T2WI sequences. LDH parameters were evaluated in relation to paraspinal muscle measurements, subcutaneous fat thickness, and BMI. Disc degeneration was classified using the Pfirrmann grading system, and statistical analysis was performed using IBM SPSS 25.0. Result: The mean age of participants was 45.6±12.3 years. Higher BMI (r=0.41) and increased subcutaneous fat thickness (r=0.46) showed a significant positive correlation with LDH severity (p<0.001). Conversely, paraspinal muscle cross-sectional area (CSA) was negatively correlated with LDH severity (r=0.49, p<0.001). Multivariate regression analysis revealed that age, sex, BMI, subcutaneous fat thickness, and paraspinal muscle CSA were statistically significantly associated with LDH (p<0.01). Subgroup analysis by sex demonstrated similar correlations between paraspinal muscle size, subcutaneous fat thickness, and LDH severity in both male and female groups. Conclusion Lumbar disc herniation severity is associated with increased BMI and subcutaneous fat thickness, as well as decreased paraspinal muscle mass. Normalized muscle parameters reduce sex-related discrepancies and establish an effective MRI-based risk assessment approach.