Three cases of siliconomas, two developing in the breast and one in the skin of the face, are reported. All occurred several months after liquid silicone injections for cosmetic and prosthetic purposes. Histopathological evidence is presented to show these reactions to be typical of a foreign body granuloma. Utilizing the polarized microscope the location of the crystals in tissue was determined and compared with similar preparations in the ape. One of the cases is presented with mammographic evidence of the silicone in the breast tissue. The evidence in respect to incidence and types of reactivity following silicone injections will not be known for many years. Because of this, the indiscriminate use of silicones should be avoided.