We study the dependence of the volume and transport of the Antarctic Bottom Water (AABW) in the Atlantic Ocean on vertical mixing. Numerical results from a set of OGCM runs show that, while the vertical extent of the AABW cell decreases with intensifying vertical mixing, the cell's transport increases. An analytical model of the deep boundary layers is then used to interpret the results. The decrease in the AABW thickness is explained by the downward expansion of the upper, North Atlantic Deep Water cell. The intensification of the AABW transport is attributed to the increase in the deep meridional pressure gradient, which drives the flow. An estimate of the AABW transport is then derived from the density balance in the deep western boundary layer and compared with the OGCM results.