The stability of the spinal column is largely dependent on the integrity of the spinal muscles, especially the multifidus muscle. However, this important role of the multifidus muscle might be compromised due to both mechanical and non-mechanical causes leading to change in its contents, fat deposition and reduction in the cross-sectional area. This study was carried out to determine the influence of physical activity level and body adiposity indices on lumbar multifidus muscle (LMM) fatty infiltration among individuals with low back pain (LBP). This was a cross-sectional study in which 94 participants, male and female samples with non-specific LBP were recruited conveniently and assessed for LMM fat infiltration, pain intensity, functional disability, physical activity and socio-demographic variables. There were positive and moderate correlations between LMM fatty infiltration body mass index (BMI) (r=0.575, p=0.001), waist circumference (WC) (r=0.514, p=0.001) and gender (r=0.409, p=0.001) for normally distributed data using Pearson moment correlation coefficient. For not normally distributed variables, LMM fatty infiltration was moderately and positively correlated with gender (r=0.422, p=0.001), %body fat (r=0.621, p=0.001), visceral fat (r=0.470, p=0.0001), Oswestry Disability Index (ODI) (r=0.238, p=0.021) and visual analogue scale (VAS) (r=0.232, p=0.024) respectively. However, there was a weak negative correlation between LMM fatty infiltration and occupation (r=p=0.046). There were significant differences between male and female multifidus fat infiltration and body adiposity indices. There was a positive relationship between multifidus fatty infiltration and BMI, gender, %body fat, visceral mass, ODI and VAS, while we observed a negative relationship between lumbar multifidus fatty infiltration and occupation. Furthermore, the best correlate of lumbar multifidus % body fat.