3,ABS TRACT Objective:The aim of this study is to compare the accuracy and effectiveness of ultrasound-(US) and fluoroscopy (FL)-guided sacroiliac joint (SIJ) injections in patients with non-inflammatory SIJ pain.Material and Methods: In this prospective randomized controlled study, 60 patients with non-inflammatory SIJ related pain were randomized into 2 groups.Patients received intra-articular SIJ injection under US or FL guidance.Primary outcomes included visual analogue scale (VAS) scores at 12 weeks after the intervention.Secondary outcomes were VAS scores at 1 week and 1 month, Oswestry Disability Index scores at months 1 and 3, Quantitative Analgesic Questionnaire and patient satisfaction at 3 months, procedure time, accuracy of needle replacement at the first attempt and number of attempts.Results: Both techniques provided significant pain reduction and functional improvement up to 3 months post-intervention compared with baseline (p<0.001), with no statistical significances between groups at any follow up point.There was no significant difference in pain medication consumption (p=0.392) and patient satisfaction scores (p=0.469) between the groups.The FL guidance for SIJ technique exhibited greater accuracy for needle replacement (93.3%) than the US (80%) at the first attempt, with no significant difference (p=0.254).Conclusion: US-guided SIJ injection with fluoroscopic confirmation is a feasible alternative to FL guidance for therapeutic SIJ injections.Patients in both groups experienced similar treatment benefits regarding pain intensity, functionality, and patient satisfaction.However, the diagnostic performance of SIJ injection alone with US guidance may be limited due to the lower accuracy rate (80%).