The multiple-data-set capabilities of the Rietveld refinement program GSAS was used to extract a quantitative texture description from a simultaneous refinement of 52 time-of-flight neutron diffraction patterns taken from a NiTi polycrystalline sample held in a variety of orientations in the diffractometer. The patterns were analyzed using a generalized spherical-harmonic model for the preferred orientation. With this method the accuracy of the available crystal structure parameters of the monoclinic B19' phase of near stochiometric NiTi (50.14 atomic % Ni) system at room temperature has been improved dramatically.