We report on the status of the calculation of deep-inelastic structure
functions at three loops in perturbative QCD. The method employed allows
to
calculate the Mellin moments of structure functions analytically as a
general
function of N. As an illustration, we present the leading fermionic
contributions to the non-singlet anomalous dimension of F_2 at three loops
and,
as a new result, to the non-singlet coefficient function of F_2 at three
loops.