Lepton Flavour Violations in SO(10) with large $\tan\beta$

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 $1\TeV$.