  We show that supersymmetry Ward identities contain an anomalous term which
takes the form of a surface term in Hilbert space. In the one-instanton sector
the anomalous term is the integral of a total rho-derivative where rho is the
instanton's size. There are cases where the anomalous term is non-zero, and
cannot be modified by subtractions. This constitutes a supersymmetry anomaly.
The derivation is based on Feynman rules suitable for any non-perturbative
sector of a weakly-coupled, renormalizable gauge theory.
