In the Minimal Supersymmetric Standard Model
(MSSM), the mass of the lightest neutralino is constrained
from collider searches to approximately 50 GeV, if the
GUT relation between the gaugino mass parameters M1 and
M2 is assumed. However, we show that the neutralino
mass is essentially unrestricted if this relation is dropped.
In this light we discuss the impact of light or massless
neutralinos on their direct production process, as well
as on electroweak precision data and rare decays.
In particular the radiative production of neutralinos at
LEP and the future linear collider will be discussed.
