  We examine the problem of gauge dependence of the 2PI effective action and
its Phi-derivable approximations in gauge theories. The dependence on the
gauge-fixing condition is obtained. The result shows that Phi-derivable
approximations, defined as truncations of the 2PI effective action at a certain
order, have a controlled gauge dependence, i.e. the gauge dependent terms
appear at higher order than the truncation order. Furthermore, using the
stationary point obtained for the approximation to evaluate the complete 2PI
effective action boosts the order at which the gauge dependent terms appear to
twice the order of truncation. We also comment on the significance of this
controlled gauge dependence.
