INTRODUCTION: We describe the first case of a patient who received AQUAfilling gel (Biomedica, Prague, Czech Republic) after augmentation with Poly Implant Prothèse (PIP) breast implants and later developed breast deformity with bilateral implant rupture. CASE REPORT: A 49-year-old Korean female patient who received breast augmentation with PIP implants 18 years ago and subsequent insertion of AQUAfilling gel 1 year ago visited our center with a chief complaint of pain and decreased implant sizes in both breasts. Breast implant and foreign body removal operation was performed for both breasts under general anesthesia. Intraoperative gross findings, pathologic findings, and tissue culture results were analyzed. RESULTS: Our diagnosis included rupture of the implants in both breasts with leakage of injected material resulting in inflammation of the pericapsular area and pectoralis muscle. The intraoperative gross findings and results of the pathologic report showed that the implants were exposed with massive leakage of AQUAfilling gel in the pericapsular space, and the pectoralis major was mixed with AQUAfilling gel-like liquid and tissue with an inflammatory reaction. CONCLUSIONS: Surgeons should be careful in performing AQUAfilling gel injection for breast augmentation, especially when combined with breast implant insertion. AQUAfilling gel itself is not yet proven safe in the long term, so more research on this topic is warranted. Additionally, surgeons should be aware of the comparatively high risk of implant rupture and foreign body reaction with PIP implants, and warn patients accordingly. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .