Plastic anisotropy of materials can be calculated from the tensile test data following two ways: (1) by the analysis of the strain ratio [gamma] vs elongation [epsilon] relationship, or (2) by relating partial strains (epsilon w and epsilon t) due to width and thickness strains to the total elongation [epsilon]. It has been shown that when based on hyperbolic description of the funkcja(epsilon) relationship, the former method (1) makes possible the precise determination of the [gamma]0 value which constitutes the anisotropy coefficient with well defined physical meaning. The latter way (2) could be useful for determining the [gamma]0 value only in the case of the fully homogeneous deformation at the tensile test when both epsilon w(epsilon) and epsilon t(epsilon) are straightlinear functions in the whole zone of uniform elongation.