$\tau - \mu - e$ Universality in $\tau$ Decays and Constraints on the Slepton Masses

The leptonic $\tau$ decays are calculated at the 1-loop level in the Minimal Supersymmetric Standard Model. The deviation from the $\tau - \mu - e$ universality is studied as a function of the supersymmetric parameters and discussed in the context of the expected improvement of the experimental accuracy.