Stereotactic vacuum-assisted breast biopsy (VAB) has been used to evaluate microcalcifications or non-palpable breast lesions on mammography. Although stereotactic VAB is usually performed in a prone or upright position, an expensive prone table is necessary and vasovagal reactions often occur during the procedure. For these reasons, the lateral decubitus position can be applied for stereotactic VAB, and true lateral mammography can be used to detect the lesion. We report on 15 cases of lateral decubitus positioning for stereotactic VAB with true lateral mammography for non-palpable breast lesions or microcalcifications. The mean procedure time was approximately 30.1 minutes, and no complications occurred during the procedures. Fourteen cases had benign breast lesions and one case had a ductal carcinoma in situ. The lateral decubitus stereotactic VAB with true lateral mammography can be applied for microcalcifications or non-palpable breast lesions and helps to minimize anxiety and vasovagal reactions in patients.