This paper describes the numerical study of the phenomenon of natural convection in an enclosure fitted with a partial vertical adiabatic partition. The partitions are parallel to the two vertical isothermal enclosure walls, which are maintained at different temperatures while the horizontal walls of the enclosure are adiabatic. The governing equations are solved with the aid of a cubic spline collocation method. Parametric studies of the effects of the partial vertical divisions on the fluid flow and temperature fields have been performed and results are presented and discussed. The heat transfer rate across the partitioned enclosure is also studied.