STUDY DESIGN: Retrospective, case series. PURPOSE: The purpose of this study is to determine morbidity, complications, and patient reported outcomes from minimally invasive sacroiliac joint (SIJ) fusion. OVERVIEW OF LITERATURE: Lumbar back pain emanating from the SIJ can be surgically treated via a percutaneous approach in the appropriately selected patient with minimal morbidity and acceptable functional outcomes. METHODS: Patients diagnosed by >2 physical examination maneuvers and subjective relief from a computed tomography-guided lidocaine-bupivacaine-steroid injection underwent SIJ fusion after failing conservative management with a combination of oral anti-inflammatory medications, physical therapy, and pelvic belt stabilization. Perioperative data collected include estimated blood loss (EBL) and operative time. Oswestry disability index, 12-item short form health survey (SF-12), visual analogue score, and functional status were analyzed. All complications were noted. RESULTS: The study cohort of 45 cases (69% female) achieved postoperative survey follow-up at 9.9 and 32.3 months. SF-12 physical component summary statistically improved while all other scores were equivalent. Mean EBL and operative time were 22 mL and 36 minutes, respectively. Initial survey showed that 64% of patients discontinued narcotics (29/45), 71% do not use an assistive device (32/45), and 15.6% do not work due to pain (7/45). 73% of patients stated they would have the surgery again (33/45). For the second survey, 65% of patients discontinued narcotics (26/40), 70% did not use an assistive device (28/40), and 17.5% did not work due to pain (7/40). A history of thoracolumbar instrumentation (16/45) did not significantly affect outcomes. Three complications described by screw malposition with neurologic deficit (6.7%) were treated with screw repositioning (1 case) and removal of a single superior implant (2 cases) with time to revision of 2.2 months. All three ultimately had resolution of radicular pain. CONCLUSIONS: Percutaneous SIJ fusion offers minimal morbidity and acceptable functional outcomes. While women and those with a prior history of lumbar instrumentation may be at increased risk of having SIJ dysfunction requiring surgical intervention, it was not found to affect postoperative functional outcomes when compared to the non-instrumented group.