The aim of imaging during and after neoadjuvant therapy is to document and quantify tumor response: has the tumor size been accurately measured? Certainly, the most exciting information for the oncologists is: can we identify good or nonresponders, and can we predict the pathological response early after the initiation of treatment? This review article will discuss the role and the performance of the different imaging modalities (mammography, ultrasound, magnetic resonance imaging and FDG-PET imaging) for evaluating this therapeutic response. It is important to emphasize that, at this time, clinical examination and conventional imaging (mammography and ultrasound) are the only methods recognized by the international criteria. Magnetic resonance imaging and FDG-PET imaging are very promising for predicting the response early after the initiation of neoadjuvant chemotherapy.