Silicone breast prosthesis with retention system, characterized in that it has a fixation means (5) based on one or several extensions of the implant, composed of a resorbable material or not and that are located in the lower part and/or posterior part -inferior of the prosthesis. (Machine-translation by Google Translate, not legally binding)1. Prótesis mamaria de silicona con sistema de retención, caracterizada por presentar un medio de fijación (5) basado en una o varias prolongaciones del implante, compuestos por un material reabsorbible o no y que se encuentran ubicados en la parte inferior y/o posterior-inferior de la prótesis.