  We consider supersymmetric extensions of the standard model with general
non-universal soft breaking terms. We analyse in a model-independent way the
constraints on these terms at the electroweak energy scale coming from gluino
mediated flavour (F) changing neutral current and CP-violating processes. We
have computed the complete $\Delta F=1$ and $\Delta F=2$ effective hamiltonian
for gluino mediated processes, including for the first time the effect of box
diagrams in the evaluation of $\epsilon^{\prime}/\epsilon$. We present
numerical results for the constraints on these non-universal soft breaking
terms for different values of the parameters, extending the analysis also to
the leptonic sector. A comparison with previous results in the literature is
given.
