  Structure of quantum corrections in ${\cal N}=1$ supersymmetric gauge
theories is investigated in the case of using the regularization by higher
covariant derivatives. It is demonstrated that this regularization allows
revealing some interesting features which lead to the exact relations between
the renormalization group functions. In particular, the NSVZ equation, which
relates the $\beta$-function to the anomalous dimension of the matter
superfields, naturally appears in this case. We briefly review the all-loop
derivation of this equation and the construction of a simple renormalization
prescription under which it is valid.
