  We review our recent work on thermal meson properties within the Chiral
Perturbation Theory framework. We will focus on the pion electromagnetic form
factor, stressing its importance for Relativistic Heavy Ion Collisions. We
obtain model-independent predictions (based only on chiral symmetry) such as
the temperature dependence of the pion electromagnetic charge radius. Imposing
unitarity allows to describe the thermal effects of resonances such as the
$\rho$ meson.
