  We present the measurements of the leptonic asymmetries in $Z^0$ decays
measured by the SLD experiment at SLAC. A data sample of approximately 550,000
$Z^0$ bosons are used for the preliminary measurement of $A_{LR}(A_{e})$ and
the leptonic final state measurements of $A_{e}$, $A_{\mu}$ and $A_{\tau}$,
representing the entire set of 1992-1998 SLD runs. When combining all results,
a preliminary value for the effective weak mixing angle is obtained:
${\sin}^2{\theta}_{W}^{eff} = 0.23109 \pm 0.00029$. We also present the direct
measurements of $A_{b}$ from left-right forward-backward asymmetries, using
partial data samples from 1993-1998 SLD runs. The preliminary value combines
jet charge, cascade kaon and semileptonic decay analyses to obtain $A_{b} =
0.866 \pm 0.036$.
