Of 187 patients with silicone breast implants 14% developed a capsular formation as late complication needing surgical therapy. Apparently neither the volume and type of prosthesis nor the operative proceeding had any influence on the formation of a constrictive capsule. No significant difference between augmentation plasty by hypo- and aplasia respectively and breast reconstruction after subcutaneous or radical mastectomy could be noticed. There has been no explanation for unilateral hypertrophic capsule formation after simultaneously performed bilateral prosthesis implantation. Compared with other authors we had a smaller incidence of the IIIrd and IVth stage capsular formation. This is caused by: 1. The advantage of a two-stage proceeding over the simultaneous one after subcutaneous mastectomy or subsequently to reconstruction by a flap plasty after radical mastectomy. 2. Systematic drainage of the bed of the prosthesis to avoid any hematoma or big liquid accumulations. Diffusion of silicone in the tissues by spontaneous rupture of the prosthesis as further late complication is discussed in 2 cases.