  The consequences of on-shell supersymmetry are studied for scattering
amplitudes with massive particles in four dimensions. Using the massive version
of the spinor helicity formalism the supersymmetry transformations relating
products of on-shell states are derived directly from the on-shell
supersymmetry algebra for any massive representation. Solutions to the
resulting Ward identities can be constructed as functions on the on-shell
superspaces that are obtained from the coherent state method. In simple cases
it is shown that these superspaces allow one to construct explicitly
supersymmetric scattering amplitudes. Supersymmetric on-shell recursion
relations for tree-level superamplitudes with massive particles are introduced.
As examples, simple supersymmetric amplitudes are constructed in SQCD, the
Abelian Higgs model, the Coulomb branch of N=4 super Yang-Mills, QCD with an
effective Higgs-gluon coupling and for massive vector boson currents.
