The results of a five-year retrospective study on breast augmentation using silicone gel-filled prostheses are presented. A total of 115 breasts (45%) out of 254 developed capsules of type II-IV. The incidence in the hypoplasia group was 46%. The capsules were treated with closed and/or open capsulotomy. Biopsies showed fibrous capsules containing alcianophilic droplets, suggesting the presence of silicone in the tissue. The authors find the above incidences to be unacceptably high, and as the treatment is costly, we advocate a more restrictive approach towards operations for mammary hypoplasia.