Mammography screening can increase survival by 15-50%. Minute nonpalpable breast carcinomas can be detected and surgically removed using precise localization techniques. Various techniques are shown, including localization by means of grid mammography and conventional localization with several needles. Stereotactic localization is recommended if the focus cannot be detected by sonography--a procedure now almost always possible if mammography units have the necessary additional equipment. In future it will often become necessary, following a good response to pre-operative chemotherapy, for the tumor, which as a result has become nonpalpable, to be marked prior to surgery (e.g. remaining microcalcifications). This is essential if a representative area of tissue is to be made available for histological examination.