BACKGROUND: The Sacroiliac Joint (SIJ) accounts for 10-27% of lower back pain. Radiofrequency neurotomy (RFN) is commonly utilized for refractory pain. Outcomes are variable and may be related to patient selection and procedural technique differences. OBJECTIVE: To assess the effectiveness and outcome success predictors of SIJ RFN at three months. DESIGN/METHODS: Data of patients undergoing SIJ RFN were extracted from the electronic medical record of one physiatrist's interventional pain practice between 2016 and 2021. The extracted data included the following outcome variables: ≥2 decrease in Numerical Rating Scale (NRS) [minimal clinically important difference MCID-2], ≥50% NRS reduction, and ≥17 points decrease in the Pain Disability and Quality of Life Questionnaire - Spine (PDQQ-S) [MCID]. Predictor variables included block type [>79% LBB/LBB, >79% IA/LBB, 50-79% LBB/LBB, 50-79% IA/LBB, >79% LBB, and 50-79% LBB] and cannula type/configuration [16 g/longitudinal, Trident bipolar/perpendicular, and 18 g quadripolar/perpendicular]. Data analysis included descriptive statistics and logistic regression with an odds ratio (OR). Covariates included in the logistic regression models were age, gender, and laterality (right, left, and bilateral). RESULTS: Of the 128 patients analyzed for this study (20.8% males; 60.4 ± 14.4 years of age), 66.9% achieved MCID-2 in NRS, 53.9% experienced ≥50% NRS reduction, and 50% experienced ≥17 points decrease in PDQQ-S. Achieving MCID-2 in NRS for the 18 g quadripolar/perpendicular technique was approximately four times higher than the odds for 16 g/longitudinal technique (OR = 3.91; 95% CI = 1.34-11.43;  = 0.013). Block type was not significantly associated with any outcome variable after adjusting for cannula type and other covariates ( > 0.05). Younger age was significantly associated with achieving MCID-2 in NRS, ≥50% NRS reduction, and ≥17 points decrease in PDQQ ( = 0.034, 0.020, and 0.002, respectively). CONCLUSION: SIJ RFN effectively reduces pain and improves function in most patients at three months. Quadripolar/perpendicular technique and younger age predict SIJ RFN treatment success, whereas block type does not.