The difficulty in indexing back-reflection Kossel diffraction patterns, especially for non-cubic systems arises from the fact that the diffraction cones do not have common vertex.Two methods which can be used for indexing diffraction patterns, both in cubic and non-cubic systems, are presented in this paper. By means of the stereographic pro-jction or computer programm described here, one can easily determine the diffraction indices of back-reflection Kossel lines.The advantage of the frst method is simple and direct. For the second method, the degree of automatization is higher, and measured data with some errors can be employed.