Low back pain is the fourth most common cause of disability-associated years worldwide. The sacral hiatus is an arched gap on the dorsal surface of the sacrum. It is a continuation of the sacral canal that contains the sacrococcygeal nerves, fibro-fatty tissue, and filum terminale. Anatomical variations of the sacral hiatus are associated with a high risk of low back pain. This study aimed to compare sacral hiatal parameters between patients with low back pain and healthy individual and determine the relationship between hiatal parameters and low back pain. A case-control study was conducted at PNS Shifa Hospital, Karachi, Pakistan, and Advanced Radiology Clinic, Karachi, Pakistan. After ethics review committee approval, 89 participants each were enrolled as cases and controls. Anteroposterior and lateral view X-rays of the lumbosacral spine were obtained. Hiatal apex and base were observed with reference to the level of the sacral vertebra. The length, width, and depth were measured using bony landmarks. There were 75 males and 103 females. The significant parameters were the hiatal shapes (p-value=0.047), apex (p-value=0.004), length (p-value<0.001) and width (p-value=0.008). The risk of low back pain was detected with shapes inverted U (O.R:1.621) and M (O.R:2.000), the apex at S1 (O.R:2.5) and S2 (O.R:1.713), base at S3 (O.R:1.33) and S4 (O.R: 1.2), variations in length, width, and depth. We identified hiatal shape, the apex and base (above S3), length (>30mm), and width (>13mm) as the risk factors for low back pain in this cohort.