Mammography is the radiographic imaging of the breast and includes screen-film mammography and xeromammography. From September 1987 to March 1990, 108 patients with breast carcinoma received mammographic examinations at Chang Gung Memorial Hospital. The spectrum of mammographic appearance included mass abnormalities (50.9%), calcifications (10.2%), a combination of mass abnormalities and calcifications (25%), asymmetrical increased density (4.6%), and parenchymal distortion (1.9%). The remaining 7.4% of the lesions lacked any radiologic sign of malignancy and primarily appeared as dense breast on the mammogram. In this series, mammography had a sensitivity of 86.1%, a specificity of 77.3% and a positive predictive value of 67.4%. Recognition of these mammographic appearances is beneficial in detecting breast carcinoma and in establishing a correct diagnosis. In addition, knowing the abilities, as well as limitations, of mammography will optimize the efficacy of this examining modality.