  We perform the analytic calculation of the Mellin moments of the structure
functions F_2 and F_L in perturbative QCD up to second order corrections and in
leading twist approximation. We calculate the 2-loop contributions to the
anomalous dimensions of the singlet and non-singlet operator matrix elements
and the 2-loop coefficient functions of F_2 and F_L. Our results are in
agreement with earlier calculations in the literature.
