Supersymmetric dark matter in the light of LEP1.5

We discuss the lower limit on the mass of the neutralino \chi that can be obtained by combining data from e^+e^- annihilation at LEP and elsewhere with astrophysical and theoretical considerations. Loopholes in the purely experimental analysis of ALEPH data from the Z peak and LEP 1.5, which appear when \mu<0 for certain values of the sneutrino mass m_{\tilde\nu} and the ratio \tan\beta of supersymmetric Higgs vacuum expectation values, may be largely or totally excluded by data from lower-energy e^+e^- data, the hypothesis that most of the cosmological dark matter consists of \chi particles, and the assumption that electroweak symmetry breaking is triggered by radiative corrections due to a heavy top quark. The combination of these inputs imposes m_{\chi} \ge 21.4~\gev, if soft supersymmetry-breaking masses are assumed to be universal at the grand-unification scale.