A numerical study of natural convection heal transfer has been conducted for air around two horizontal heated cylinders confined to a rectangular enclosure cooled from above. Two cavity widths and three different top cylinder positions were investigated. The local and average Nusselt numbers are determined over the range of Rayleigh numbers from 10* to Iff. Results show the complexity of convective motion for different geometric configurations and the effects of the cylinder positions and the Rayleigh number on the local and overall heat transfer rates.