BACKGROUND: Patient-reported outcome measures (PROMs) are increasingly employed in healthcare to assess outcomes. The BREAST-Q Implant Surveillance module (BREAST-Q IS) is a 5-question PROM utilized by the Australian Breast Device Registry to monitor the performance of breast devices. Validation of this tool is needed to assess its utility in this setting. OBJECTIVES: The objective of this study was to assess the test-retest reliability of the BREAST-Q IS among breast implant recipients within a registry setting. METHODS: A test-retest reliability study was undertaken. Patients who underwent breast augmentation or breast reconstruction and registered with the Australian Breast Device Registry were eligible to participate. A total of 250 surveys were distributed. The BREAST-Q IS was administered to the same group of participants on 2 separate occasions with a 2-week test interval. Participants were divided into 2 groups: breast augmentation and breast reconstruction. A weighted kappa coefficient was calculated to assess the degree of test-retest reliability of the BREAST-Q IS. RESULTS: A total of 207 participants completed both tests. The response rate was 82% (n = 113) for the breast augmentation group and 94% (n = 94) for the breast reconstruction group. All 5 questions on the BREAST-Q IS obtained weighted kappa scores above 0.74 among both groups. CONCLUSIONS: The BREAST-Q IS has good to excellent test-retest reliability for utilization among breast implant recipients in a registry setting. Further validation of the BREAST-Q IS will be required to establish the BREAST-Q IS as a valid and reliable PROM tool for breast implant recipients following breast device surgery.