It is planned to start screening mammography throughout Japan in the near future. However, a minimally invasive biopsy procedure for mammographically detected non-palpable breast lesions is not available in almost all Japanese hospitals. It is crucial to develop a useful minimally invasive biopsy method which can be applied without difficulty. Eighty-nine biopsies for 88 mammographically detected non-palpable breast lesions, consisting of 70 lesions with microcalcifications alone, eight masses without calcifications and 10 with both masses and microcalcifications, were performed using the combination of a vacuum-assisted biopsy device (Mammotome) and an upright-type stereotactic mammography unit. Microcalcifications were confirmed radiographically in the tissue obtained from 78 biopsies among 81 biopsies for the lesions with microcalcifications (96.3%). All the lesions without calcifications were considered to be biopsied successfully. Five patients complained of nausea or fainted during the localization or biopsy procedure and an additional patient suffered from hyperventilation syndrome. Five cases experienced mild subcutaneous bleeding in the breasts. The biopsy technique using the combination of a vacuum-assisted biopsy device and an upright-type stereotactic mammography unit is a cost-effective, safe and very useful method for mammographically detected non-palpable breast lesions. It is expected to be a standard method of biopsy for such lesions in many developed countries other than the USA. However, it is important to make the patients relaxed during the biopsy to prevent mental strain.