Background: Bilateral Hamstrings muscles shortening is a common condition found in symptomatic and asymptomatic subjects. Tightness of this muscle can play a role in low back pain, postural deficits, lumbar spine disorders and sport related injuries. Purpose of this study: was to investigate the influence of bilateral hamstrings muscles shortening on some radiological parameters of lumbosacral spine. Materials and Methods: Thirty normal subjects of both genders participated in this study. Subjects were classified into two equal groups; Group A: The Control group: was consisted of fifteen subjects. They were without hamstring shortening with mean age, weight, height and BMI were 26.8 ± 4.34 years, 74.6 ± 17.45 kg, 174 ± 15.5 cm , and 24.28 ±2.67 kg/m2 respectively. Group B: The Study group: was consisted of fifteen subjects. They were with bilateral shortening of the hamstrings with mean age, weight, height and BMI were 25.8 ±3.91 years, 66 ± 9.69 kg, 164.2 ±7.43 cm , and 24.38± 2.81 kg/m2 respectively. The shortening of the hamstrings was assessed with Active Knee Extension Test, and radiological parameters of lumbosacral spine were assessed from X-Ray image using Paxera Viewer Software. Results: This study showed that there was a significant difference in some radiological parameters of lumbosacral spine ( Lumbar lordosis angle, Lumbosacral angle and Sacral inclination angle) in cases of bilateral hamstrings muscle shortening as p value was (
: Hamstring flexibility, Lumbosacral spine, Sacral Inclination Angle, Lumbar Lordosis Angle, Lumbosacral Angle.