Background: Sacroiliac (SI) joint pain conservative treatments show poor outcomes. Hypothesis: surgical treatment will show better results. Patients and methods: Prospective series: 24 patients undergoing SI fusion after failure of medical treatment and showing temporary relief with SI infiltration. Period: Nov 2009-July 2013. Gender: 9/15. 11 cases bilaterally (all ). Age: 32-71 years (mean 47.4 years). Height: 161-178 cm (mean 168.2 cm). Weight: 56-84 kg (mean 68.4 kg). Etiology: 12 degenerative/spontaneous, 7 fall on buttocks, 3 coincident with lumbar disc and 2 with lumbar posterolateral fusion. Exclusion criteria: ankylosing spondylitis, osteitis condensans ilii, sacro-iliac joint arthropaty. Demographics, analgesics and NSAID's consumption, incidence and severity of complications, clinical outcome using a visual analog scale (VAS) for pain, Oswestry Disability Index (ODI) and time to returning to work were collected postoperatively at 1, 3 and 6 months, and then at six months interval until last follow-up. Results: Follow-up: 1-4.5 years (mean 23.3 months). No intra-operative or post-operative major complications. No blood transfusions. Patients stayed over-night, and discharged next morning. No crutches used. Time to returning to work: 47.4 days (range 30-67 days). Post-op: marked reduction in VAS and analgesic consumption (preop 8.7, post-op 1 month 3.2, 3 months 2.8, 6 months post-op 2.1, 12 months 1.7, 18 months 1.7, 2 years 1.9, 2½ years 1.8, 3 years 2.0, at 3½ years 2.1, 4 years 2.1 and 4½ 2.1). Mean ODI scores improved from 54.1 preoperatively to 23.9, 21.2, 20.4 and 14.3 at 1, 3, 6 and 12 months postoperatively, and 15.1, 15.5 15.8, 16.0, 16.1, 16.3 and 16.3 at 1½, 2, 2½, 3, 3½, 4 and 4½ years (p<.001). 1 year post-op 22/24 patients would undergo the procedure again. Conclusion: Percutaneous SI joint arthrodesis is effective and safe to treat chronic SI joint pain.