A steady state natural convection heat transfer is numerically investigated in a two-dimensional square enclosure. One of the side walls of the enclosure is brought to high temperature and the upper wall is insulated. The other walls are partially insulated and the remaining parts of those walls are kept cold in accordance with the area of cold and hot surfaces are equal. The solution is performed for Rayleigh number values between 104 and 106, and for a Prandtl number value of 0.71. The obtained results are presented as local and average Nusselt numbers, streamlines, isotherms and heatlines. It is found that cold and insulated wall configurations have noticeable effects on the flow temperature fields and resulting heat transfer.