Sacroiliac joint (SIJ) pain is one of the underappreciated causes of low back pain. Recent studies have reported excellent outcomes after Ultrasound (US) guided SIJ injection with local anesthetics and corticosteroids, but these studies are characterized by wide variability in selection criteria and patient characteristics; therefore, there is a need to determine whether any demographic or clinical variables can be used to predict US-guided SIJ injection outcomes.