Real-time tissue elastography is an emerging diagnostic tool that uses ultrasound to differentiate between hard and soft tissue. Typically, gentle freehand compression is used to apply 'stress' to tissue and the resulting 'strain' or displacement, is displayed as a colour overlay on a conventional B-mode ultrasound image. Elastography has the potential to increase examination specificity and thus reduce the need for diagnostic invasive procedures. Second generation technology, which quantifies strain characteristics, is bringing further improvements in diagnostic accuracy. Real-time tissue elastography has proven applications in breast, prostate, thyroid and pancreatic disease and where diagnostic biopsy is indicated, elastography allows more accurate localisation and targeting of lesions. This paper briefly reviews the underlying principles of the technique and outlines the current clinical applications.