Direct radiographic magnification (1.5 X) of the breast with a microfocus x-ray tube was compared with conventional contact mammography. Measurements of modulation transfer functions, Wiener spectra, scattered radiation, and dosimetry permitted quantitative comparisons of resolution, noise, contrast, and patient exposure. Images of surgical specimens of the breast, and the breasts of 125 patients, were qualitatively compared. Magnification images were superior (increased resolution, reduced noise) to conventional mammography images, at the expense of increased radiation dose. Clinical study revealed that the superior magnification image is useful in distinguishing malignant from benign breast disease, in selected cases.