Introduction Sacroiliac joint (SIJ) pain is a common source of low back pain. Though this condition can be treated with conservative measures, there is a subset of patients who fail to respond to conservative treatment. For them, surgical treatment using minimally invasive techniques could be considered. There are currently a number of SIJ fixation methods described. However, there is no case series reported on posterior oblique approach. Therefore, in this paper, the authors report their experience with the Sacrix system via the posterior oblique approach. Method In this series, 19 patients aged 44-84 years, with a median of 58 years, underwent SIJ fusion using this technique. This is a posterior oblique approach in which two screws are inserted into the ilium through the posterior part of the iliac crest and then advanced into the sacrum through the SIJ. Results The follow-up is between 7 and 30 months, with a median of 12 months. Eighteen patients had excellent pain relief. There was no complication from the procedure, and the blood loss was minimal. All eight patients who had follow-up radiographs showed solid fusion. Conclusion Posterior oblique approach for SIJ fusion is a minimally invasive procedure that proved to be effective and safe in this series. It also resulted in solid radiographic fusion, decreased pain, and improved function.