  The $B^0$-$\bar B^0$ oscillation frequency has been measured with a sample of
23 million $\B\bar B$ pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives $\Delta m_d =
0.493 \pm 0.012{(stat)}\pm 0.009{(syst)}$ ps$^{-1}$.
