Sonoelastography is an imaging technique which utilizes Doppler ultrasound to estimate the peak displacement of the tissue under an externally induced mechanical harmonic excitation. The underlying assumption is that healthy and pathologic tissue will respond differently to this excitation. In this article, we review the state of the art on this technique and present the latest results on different clinical applications. Clinical research in sonoelastography has focused primarily on prostate cancer detection. Sonoelastography showed an accuracy of over 80% for finding tumors in vivo and ex vivo larger than 4 mm in diameter. These results are an improvement over B-mode and suggest that sonoelastography can be used to guide biopsies. Another clinical application for sonoelastography is to image thermally ablated lesions in liver in vitro and in vivo. The measurements performed with sonoelastography had over 90% correlation with the size of the lesions in the gross pathology images. © 2010 IEEE.