This paper presents an experimental investigation on the effect of different types of partitions on the natural convective heat transfer in enclosures. The enclosure was fitted with a partition midway between two vertical isothermal walls, one of which was heated and the other was cooled. The remaining walls of the enclosure were insulated. Different configurations of partitions were used, and these include a partition with a central rectangular opening, a partition with lateral rectangular opening, and a partition with a central arch aperture. The experiments were conducted using air as the working fluid over a Rayleigh number range of 6 x 10(7) to 1.3 x 10(8) with an aspect ratio (height/length) of 0.5. Empirical correlations were obtained for these cases, which were found to agree well with the correlations of the literature. The results indicated that the location of the opening and the aperture height ratio (aperture height/enclosure height) have both a significant effect on the heat transfer, while only a limited effect of aperture width ratio (aperture width/enclosure width) was noticed,