Mathematical models for simulation and control of systems and mechanisms naturally arise in a descriptor form. The stability analysis of descriptor systems, involving free parameters as uncertainties or design qualifiers is subject of this paper. Two approaches for the calculation of the stability boundaries in the underlying parameter space are discussed. The first one uses a quantifier elimination method, while the second one is based on the direct solution of the Lyapunov equation. The computational methods are exemplary demonstrated on Chua’s circuit.