BACKGROUND: The purpose of this retrospective analysis of a prospective quality control project was to determine whether the use of intrawound vancomycin powder (IVP) decreases the rate of periprosthetic joint infection (PJI) within 90 days following primary total hip arthroplasty (THA). METHODS: From October 2021 to September 2022, a prospective quality control project was undertaken in which 10 high-volume THA surgeons alternated between using and not using IVP each month while keeping other perioperative protocols unchanged. A retrospective analysis of the project was performed to compare the group of patients who received IVP to the group of patients who did not. The primary outcome was a culture positive infection within 90 days following primary THA. Secondary outcomes included gram-positive culture, overall reoperation rate, wound complications, readmission, and wound complications within 90 days post-operatively. A total of 1,193 primary THA patients were identified for analysis. There were 523 (43.8%) patients who received IVP and were included in the IVP group, while 670 (56.2%) did not and were included in the non-IVP group. Age, body mass index, and sex were similar between the 2 groups (P > .25). RESULTS: The IVP group had a higher rate of culture positive joint infections (1.7 [0.8, 3.2] versus 0.3% [0.04, 1.1], P = .01) than the non-IVP group. All PJI's were found to have gram positive bacteria in both groups. The IVP group had a higher overall reoperation rate than the non-IVP group (6.1 [4.2, 8.5] versus 2.4% [1.4, 3.9], P < .01). The IVP group had a higher reoperation rate for any wound complication compared to non-IVP patients (2.7 [1.5, 4.5] versus 0.7% [0.2, 1.7], P < .01). The overall readmission rate (6.1 [4.2, 8.5] versus 2.8% [1.7, 4.4], P < .01), as well as readmission for suspected infection (2.1 [1.1, 3.7] versus 0.6% [0.02, 1.5], P = .03), were higher in the IVP group. CONCLUSIONS: The use of IVP in primary THA was associated with a higher rate of PJI, overall reoperation, reoperation for wound complications, and readmission in a prospective quality control project. Until future prospective randomized studies determine the safety and efficacy of IVP in THA conclusively, we advocate against its utilization.