This letter concerns a generalization of the method presented in recent papers for the determination of the galvanomagnetic coefficients, especially those of magnetoresistance, for the case of crystals with low symmetry. The central idea is the search of one of the principal directions of the zero‐field resistivity and the application of the Wasscher method for anisotropic materials in a circular flat sample containing the other two principal directions. The determination of the magnetoresistance coefficients is obtained by the peculiar influence of the magnetic field on the resistivity anisotropy leading to the magnetoresistance skewness effect.