The evolution of residual stress and crystallographic texture during thermal treatment was studied using X-ray diffraction. Polycrystalline α-brass samples were examined after cold rolling and afterwards after annealing at different temperatures in the range of 50 0C - 450 0C. Additionally, the width of the diffraction peak was measured in order to estimate the variation of the dislocation density. The interpretation of experimental data was based on a fitting procedure for which the anisotropic diffraction elastic constants calculated by a self-consistent approach were used. As the result of analysis, the values of the first order and second order stresses were determined in each sample.