The exposures to surface of 6 cm compressed breast, in a survey of widely differing mammographic techniques, are statistically compared by type of receptor utilized. It was found that although skin exposures differ widely, the exposure to receptor surface for techniques acceptable to radiologists, fall in a narrow range depending on the receptor and the x-ray equipment used. Assuming breast tissue to have composition equivalent to 5O% fat and 5O% muscle, depth exposure values have been calculated from measurements of Boag, et al 6 for four different spectra relevant to mammography. From the values of exposures required at the surface of different receptors, the depth exposure values and the energy fluence per Roentgen in the spectra considered, the skin exposures and energy retained per amt for 6 cm breast have been calculated. The possibilities of reduction of skin exposure or the energy retained in the breast tissue by choice of receptor, mammography equipment, and optimum radiographic techniques are discussed.