The results of real-time hand-held sonographic breast examinations on 86 patients are presented. The technique is described in detail. Sonography was found to be a useful adjunct to the x-ray mammogram in three groups of patients: (1) patients with dense breasts and localized symptomatology or a suspicious area on x-ray mammogram; (2) patients with nonpalpable abnormalities discovered on x-ray mammogram; and (3) patients with palpable masses considered indeterminate on x-ray mammogram. The examination was also found useful for guiding needle aspiration biopsies, in patients with persistent nipple discharge, and in those with breast prostheses. Advantages of the hand-held real-time technique include supine positioning, the ability to flexibly orient the probe, improved resolution due to higher frequency transducers and the lack of compounding, and the ability to vary the amount of compression to assess tissue compliance and fixation. The disadvantage of decreased resolution in the near field can be overcome by attaching a detachable water-path step-off device to the transducer. Geometric distortion from the pressure of the transducer was not believed to be a problem. Hand-held sonographic technique is useful when attention can be directed to a specific area of the breast. The additional information provided results in fewer equivocal interpretations of the x-ray mammogram; however, it should not be used as a substitute for routine mammography.