The aim of this work has been to evaluate whether a diagnostic protocol based on the joint use of mammography and ^99mTc-MIBI scintimammography can help to distinguish the lesions and to reduce the number of biopsies required in patients with suspected breast cancer. A total of 58 women were evaluated by palpation, mammography, scintimammography. Twenty-four patients were scintimammographed with ^99mTc-MIBI at 10 min after injection. Thirty-four patients were taken double-phase scintimammography with ^99mTc-MIBI 10 min and 60~90 min after injection. Based on mammography, the supicion degrees of malignancy were rated, and 30 results of malignancy were confirmed by histopathology. Based on mammography, 18 lesions were considered to be most probably benign (of which 3 were histopathologi-cally breast cancer), 19 as indeterminate (of which 9 were histopathologically breast cancer), and 21 as malignant (of which 18 were histopathologically breast cancer). The results of early and delayed phases ^99mTc-MIBI scintimammography were the same. The sensitivity, specificity and accuracy of scintimammography were 74.29%, 86.96% and 79.31%, respectively. Scintimammography gave 16 correct diagnosis in 19 mammogram indeterminate (84.2%) and demonstrated 5 out of 8 cases axillary lymph nodes metastasis (62.5%). These studies show that ^99mTc-MIBI scintimammography used as a complementary testing technique to mammography is useful in the examination of patients with suspected breast cancer. The adoption of a joint mammography-scintimammography diagnostic protocol could considerably reduce the number of biopsies performed in patients with lesions of indeterminate mammographic suspicion of malignancy.