BACKGROUND Minimally invasive sacroiliac joint fusion is increasing significantly. Starting January 1, 2015, it has a category I CPT code. The current RVU for this procedure is not equal to the amount of work involved. There is not a published RUC validated survey to establish the work effort of MI SI fusion. Our hospital system has been doing this procedure for 4 years and has been tracking surgeon time through a commercial tracking system (Navicare). Our study looks at time utilization for performance of MI SI joint fusion and a comparator of primary lumbar discectomy (PLD), presumably similar in time and work effort. METHODS This study was a retrospective review of prospectively collected data using Navicare. The data for 3 surgeons who perform MI SI joint fusion and lumbar discectomies from January 1, 2013 through November 30, 2014 was retrieved. Surgeon room time was identified as the time the patient entered the OR to the time they exited the OR. This was used as opposed to skin to skin time seen in similar studies as it was more accurately and consistently recorded in the medical record. Mean and standard deviations were then compared using student's t-test. RESULTS In 50 primary MI SI joint fusions, the average in-room time was 112 minutes (SD=23). In 89 cases of PLD, the average in-room time was 119 minutes (SD=26). When comparing mean in-room times, MI SI and PLD were not statistically significantly different (p=0.135, 2-tailed t-test). Post-operative work effort was found to be greater for MI SI joint fusion than PLD. CONCLUSIONS / LEVEL OF EVIDENCE Surgical time was found to be comparable between MI SI joint fusion and PLD, while work effort was found to be greater for MI SI joint fusion. This signifies at a minimum an equal RVU for PLD should be used for MI SI joint fusion. This study was approved by the Institutional Review Board at the University of Minnesota. LEVEL OF EVIDENCE 3.