  We present time-resolved optical spectroscopy and photometry, and
far-ultraviolet spectroscopy of HS 0728+6738, a cataclysmic variable discovered
in the Hamburg Quasar Survey. We show that the system is a new eclipsing member
of the SW Sex class of CVs with an orbital period of 3.21 hours. We derive an
orbital inclination of ~85 +- 4 degrees from the average eclipse profile,
making HS 0728+6738 the highest inclination SW Sex star known. The optical and
far-ultraviolet emission lines are not or only weakly occulted during the
eclipse, indicating the presence of line-emission sites either far outside the
Roche lobe of the primary or, more likely, above the orbital plane of the
binary. The photometric light curves exhibit fast variability with a period of
\~7 min, which might be related to the spin of the white dwarf.
