Breast ultrasound elasticity evaluation has become a routine tool in addition to diagnostic ultrasound during the last five years. Two elasticity evaluation modes are currently available: free-hand elastography and shear-wave elastography (SWE). Most of the commercially available elastography scanners have specific procedures which must be understood by the users. Free-hand elastography usually displays qualitative imaging such as an elastogram, but most of the companies now use it to quantify the relative stiffness between a lesion and the surrounding breast tissue. SWE is a new mode theoretically independent of the sonographer which displays more quantitative information, and can be useful for characterizing breast lesions. Recent studies on elastography suggest that elasticity imaging can increase B-mode accuracy and specificity in differentiating benign and malignant breast lesions. This functional imaging mode could help reduce the number of biopsies performed for benign breast lesions. This review gives a detailed description of the main commercially available systems and the results of current applications in the evaluation of breast elasticity.