  We perform direct diagrammatic calculations of the anomalous dimensions of
twist-two operators in extended N=2 and N=4 super Yang-Mills theories (SYM). In
the case of N=4 SYM, we compute the four-loop anomalous dimension of the
twist-two operator for several fixed values of Lorentz spin. This is the first
direct diagrammatic calculation of this kind, and we confirm results previously
obtained by means of integrability. For N=2 SYM, we obtain the general result
for the anomalous dimension at third order of perturbation theory and find the
three-loop Cusp anomalous dimension.
