Purpose: Human skin consists of several layers including epidermis, dermis, and hypodermis. The determination of the in vivo mechanical properties of an individual skin layer represents a great challenge to date. In this study, the authors explore the use of the supersonic shear imaging (SSI) technique and inverse analysis to determine the in vivo elastic properties of the dermis layer of human skin. Methods: The measurements are conducted on the volar forearms and dorsal forearms of 18 healthy volunteers (nine females and nine males) using the SSI technique that gives the velocities of the shear wave generated by the acoustic force. Finite element analysis is carried out to simulate the propagation of the shear wave in the multilayer soft media and the results are used to interpret the experimental data and deduce the shear modulus of the dermis layer. Results: The shear moduli of the skin dermis layer obtained for the 18 healthy volunteers exhibit significant anisotropy. A standard statistical analysis demonstrates the differences between sexes. Conclusions: This study demonstrates that the SSI technique together with the inverse analysis represents a useful tool to characterize the in vivo elastic properties of human skin. (C) 2015 American Association of Physicists in Medicine.