  We define a diophantine condition for interval exchange transformations
(i.e.t.s). When the number of intervals is two, that is for rotations on the
circle, our condition coincides with classical Khinchin condition. We prove for
i.e.t.s the same dichotomy as in Khinchin Theorem. We also develop several
results relating the Rauzy-Veech algorithm with homogeneous approximations for
i.e.t.s.
