Optical Coherence Elastography (OCE) is an emerging technique that allows noninvasive assessment of tissue biomechanical properties with high lateral and axial resolutions. Previous attempts to measure tissue elasticity, compressibility, and shear forces in vivo have met with limited success and little agreement. Successful in vivo measurements of the biomechanical properties of different tissues could lead to many significant scientific and clinical breakthroughs in our understanding of disease development and progression, and the impact of clinical treatments. OCE can image nanometer level tissue displacements induced by localized compression forces. Phase-sensitive OCT has been demonstrated capability to assess nm-amplitude mechanical waves propagating on tissue surface. Under this project, we are developing methods to quantify elastic wave parameters produced by focused stimulation (air or ultrasound) in different samples and tissues ex vivo, in vitro and in vivo using a Phase Stabilized Swept Source Optical Coherence Elastography (PhS-SSOCE) technique. Our results demonstrate that PhS-SSOCE has great capability to assess tissue elasticity and differentiate tissues based on the Young modulus. This gives additional contrast to standard OCT imaging capabilities and can increase increasing specificity and sensitivity in tissue classification efforts.