  Starting from superdifferential operators in an $N=1$ superfield formulation,
we present a systematic prescription for the derivation of classical $N=1$ and
$N=2$ super W-algebras by imposing a zero-curvature condition on the connection
of the corresponding first order system. We illustrate the procedure on the
first non-trivial example (beyond the $N=1$ superconformal algebra) and also
comment on the relation with the Gelfand-Dickey construction of $W$-algebras.
