  The accretion column in magnetic Cataclysmic Variables may have a not
negligible Thomson optical depth. A fraction of the thermal radiation from the
post-shock region may therefore be scattered - and then polarized - before
escaping the column. Moreover, part of the thermal radiation is reflected - and
again polarized - by the White Dwarf surface. We show that X-ray polarimetry
can provide valuable, and probably unique informations on the geometry and
physical parameters of the accretion column by calculating, by means of Monte
Carlo simulations, the expected polarization properties of magnetic CVs as a
function of the geometrical parameters (assuming a cylindrical geometry) and
the Thomson optical depth of the column. We find that degrees of polarization
as high as about 4% can be present, and apply our calculations to the
archetypal magnetic CV, AM Herculis.

Astrophysics