Purpose: We attempt to assess the differences in the degree of lumbar lordosis in patients with lower back pain caused by the herniation of the nucleus pulposus and in normal people (divided into male and female groups). Methods: This study was conducted with 14 patients (7 males, 7 females) diagnosed with, and being treated for, lumbar herniated nucleus pulposus and 14 normal people (7 males, 7 females). In order to examine the degree of lumbar lordosis in these subjects, hip flexor lengthening tests were conducted and the lumbar curves were measured in three postures (supine, sitting, and prone) and the results were compared. Results: The measured values of the curves for the standing and prone postures showed statistically significant differences between the normal group and the patient group, between the normal male group and the male patient group, and between the normal female group and the female patient group (p<0.05). Conclusion: The measurement method that uses flexible curve rulers in the standing or prone postures can be usefully utilized in assessing the lumbar lordosis of patients with lumbar herniation of the nucleus pulposus.