  In supersymmetric~SO(10) with large $\tan\beta$ and Yukawa coupling
unification $\lambda_t=\lambda_b=\lambda_\tau$, we compute the rates for lepton
flavour violating processes. Experiments in progress or foreseen for $\mu\to
e\gamma$, $\mu\to e$ conversion (and the dipole moment of the electron) are
shown to provide very significant tests of the theory for all slepton masses up
to about $1\TeV$.
