BACKGROUND: The sacroiliac joint complex (SIJC) is considered a major sources of chronic low back pain. Interventional procedures for sacroiliac (SI) joint pain tend to be short-lived and surgical treatment usually involves a fusion procedure. OBJECTIVES: To determine the clinical efficacy of endoscopically visualized radiofrequency treatment of the SIJC in the treatment of low back pain. STUDY DESIGN: Retrospective chart review. SETTING: This study took place in a single-center, orthopedic specialty hospital. METHODS: Patients received general anesthesia and under endoscopic visualization, radiofrequency ablation was performed on 1) the perforating branches that innervate the posterior capsule of the SI joint capsule, 2) along the course of the long posterior SI ligament, 3) the lateral edges of the S1, S2, and S3 foramen, and 4) the L4, L5, and S1 medial marginal nerve branches along the lateral facet margins. RESULTS: From January 2015 to June 2016, a total of 30 patients who met the precise inclusion criteria were treated with the endoscopic SIJC radiofrequency treatment for low back pain. The average patient was aged 56 years (19 women and 11 men), the average preoperative visual analog scale (VAS) score was 7.23, and the average Oswestry disability index (ODI) score was 44.8. VAS and ODI were measured at 3, 6, 9, 12, 15, 21 and 24 months: VAS was reduced from 7.23 at baseline to 2.82 at 24 months (61% reduction), and ODI was improved from 44.8 at baseline to 22.2 at 24 months (50% reduction). LIMITATIONS: Small retrospective case series. CONCLUSIONS: Full-endoscopic radiofrequency ablation of the large sensory SI joint innervation complex, that includes the sensory nerve branches along the lateral S1-3 foramina and the L4-S1 medial branches, is perhaps a minimally invasive surgical procedure that could provide significant relief of lumbar back pain in the carefully selected patient. KEY WORDS: Endoscopic spine surgery, minimally invasive, low back pain, sacroiliac joint, radiofrequency treatment.