Laminar natural convective heat transfer within a two-dimensional rectangular enclosure with horizontal conducting walls and partitions was investigated by numerical analysis and experiment. The enclosure consists of two isothermal vertical walls and two adiabatic horizontal walls. This combined heat transfer problem of conduction and natural convection was solved using finite difference method with SIMPLE algorithm, and temperature distribu-tions in the air filled enclosure was obtained using Mach-Zehnder interferometer. Good agree-ment was obtained between the predicted and measured results. The effect of geometric parameters and thermal properties on heat transfer was studied far Grashof numbers in range, $1 imes10^4;{leqslant};G^r;{leqslant};6.4 imes10^5.$ It was found that both velocity and temperature fields were in-fluenced significantly by thermal conductivity of the conducting walls and the partitions, and by geometry of partitions.