In this paper, I report a case of delayed slow leakage (partial deflation) from an inflatable saline breast implant, 12 years after augmentation mammaplasty. The patient had a history of breast foreign body injection and developed a complication with multiple painful indurated mass. She received a subcutaneous mastectomy to remove all the injected breast foreign body in November 1986 and an inflatable breast implant was given for augmentation simultaneously. Owing to the accidental deflation of the left implant, the breast implant was removed and replaced in January 1999. Examination of the removed breast implant revealed a linear fold (13 cm in length) on the lower pole of the prosthesis and a small leaking hole (microscopic tear) in the middle of that fold. The possible mechanisms of implant deflation may include faulty manufacturing process, fold flaw leak (crease fold failure) and capsular contracture. In this case report the capsular contracture had caused prosthesis folding and the prosthesis had become partial deflation finally. Besides the better surgical intervention to prevent capsular contracture, I believe that choosing a correct implant size preoperatively and filling that implant to its optimal level will best minimize the possibility of breast silicone shell folding.