To explore the impact of PMRT on PROs of IBBR performed with and without mesh. PMRT is increasingly given to improve breast cancer outcomes but can adversely impact complications after IBBR.Little; however, is known about the impact of PMRT on the PROs of IBBR, especially when mesh is used. The implant Breast Reconstruction evAluation prospective cohort study recruited consecutive women undergoing immediate IBBR from 81 UK breast and plastic surgical units. Demographic, operative, oncological, and 3-month complication data were collected, and patients consented to receive validated PRO questionnaires at 18-months. The association between IBBR, PMRT, and PROs were investigated using mixed-effects regression models adjusted for clinically-relevant confounders and including a random-effect to account for potential clustering by center. A total of 1163 women consented to receive 18-month questionnaires of whom 730 (63%) completed it. Patients undergoing PMRT (214 patients) reported worse PROs in 3 BREAST-Q domains: satisfaction with breasts [-6.27 points, P = 0.008, 95% confidence interval (CI) (-10.91, -1.63)], satisfaction with outcome [-7.53 points, P = 0.002, CI (-12.20, -2.85)] and physical well-being [-6.55 points, P < 0.001, CI (-9.43, -3.67)]. Overall satisfaction was worse in the PMRT group [OR 0.497, P = 0.002, CI (0.32, 0.77)]. These effects were not ameliorated by mesh use. PMRT may adversely affect PROs after IBBR irrespective of whether mesh is used. These findings should be discussed with all patients considering IBBR and when indications for PMRT are borderline to enable informed decision-making regarding oncological and reconstructive treatment options. ISRCTN37664281.