  Azimuthal asymmetries measured in unpolarized semi-inclusive deep inelastic
scattering bring important information on the inner structure of the nucleons,
and can be used both to estimate the average quark transverse momentum k_T and
to access the so-far unmeasured Boer-Mulders functions. COMPASS results using
part of the 2004 data collected with a 6LiD target and a 160 GeV positive muon
beam are presented separately for positive and negative hadrons.
