We reconstruct (B) over bar (0)-> Ds-D+ decays using a sample of 449x10(6) B (B) over bar pairs recorded by the Belle experiment, and measure the branching fraction to be B((B) over bar (0)-> Ds-D+)=[7.5 +/- 0.2(stat)+/- 0.8(syst)+/- 0.8(B(')s)]x10(-3). A