  We consider the two-body problem in post-Newtonian approximations of general
relativity. We report the recent results concerning the equations of motion,
and the associated Lagrangian formulation, of compact binary systems, at the
third post-Newtonian order (1/c^6 beyond the Newtonian acceleration). These
equations are necessary when constructing the theoretical templates for
searching and analyzing the gravitational-wave signals from inspiralling
compact binaries in VIRGO-type experiments.
