Within the grand canonical ensemble, we use a general quantum statisti
cal formula and the thermodynamic Green's functions to derive a pertur
bation expansion for the pressure of a multicomponent plasma. Differen
t contributions to the equation of state (EOS) are given analytically
and by numerical calculations. Exact results for the EOS are presented
in the shape of a low-density expansion up to the order (ne(2))(5/2),
including ladder-type contributions and ''beyond Montroll-Ward'' term
s.