  We report measurements of the magnetoresistance in the charge density wave
(CDW) state of rare-earth tritellurides, namely TbTe$_3$ and HoTe$_3$. The
magnetic field dependence of magnetoresistance exhibits a temperature dependent
crossover between a conventional quadratic law at high $T$ and low $B$ and an
unusual linear dependence at low $T$ and high $B$. We present a quite general
model to explain the linear magnetoresistance taking into account the strong
scattering of quasiparticles on CDW fluctuations in the vicinity of "hot spots"
of the Fermi surface (FS) where the FS reconstruction is the strongest.
