  A complete classification of generalized symmetries of the Yang-Mills
equations on Minkowski space with a semi-simple structure group is carried out.
It is shown that any generalized symmetry, up to a generalized gauge symmetry,
agrees with a first order symmetry on solutions of the Yang-Mills equations.
Let $g=g_1+...+g_n$ be the decomposition of the Lie algebra $g$ of the
structure group into simple ideals. First order symmetries for $g$-valued
Yang-Mills fields are found to consist of gauge symmetries, conformal
symmetries for $g_m$-valued Yang-Mills fields, $1\leq m\leq n$, and their
images under a complex structure of $g_m$.
