In this note, it is shown that instead of a bilinear transformation, a biquadratic transformation can be used to determine the Schur stability of a given discrete-time polynomial by determining the Hurwitz stability of the corresponding continuous-time polynomial. However. using a biquadratic transformation, the analysis is not limited by any restriction on the root positions. Several numerical examples are provided to illustrate the procedure. (C) 2004 Elsevier Ltd. All rights reserved.