A nanoscale technique for the measurement of stresses has been developed for use in crystalline structures of arbitrary complexity. This has been accomplished by quantitative comparison of transmission electron microscopy (TEM) experimental images with simulations of electron diffraction contrast based upon solutions of the Howie-Whelan equations for finite element method (FEM) generated displacement fields. This procedure allows a quantitative determination of stress fields with nanoscale spatial resolution and ±15 MPa stress sensitivity.