The effect of buoyant forces on viscous coarsening is studied numerically. It is shown that at any time buoyant forces induce a vertical flow that scales like the Stokes velocity. This does not induce any noticeable change in the morphology of the coarsening microstructure under a value of the characteristic length of the pattern. Above this threshold, the pattern evolves toward a quasi 2D pattern and coarsening stops. The characteristic length is shown to scale like [Formula: see text], where γ is the surface tension and [Formula: see text] is the mass density difference between the phases.