The B0--B0 oscillation frequency has been measured with a sample of 23*106 B-B pairs collected with the BABAR detector at the PEP-II asym. 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 Dmd=0.493+-0.012(stat )+-0.009(syst) ps-1. [on SciFinder (R)]