Tropical forests are major reservoirs of biodiversity. Soil microbes play important roles in soil fertility. Microbes are sensitive to changes in agricultural activities occurring in the soil, thus they can be used as an indicator for soil quality. This study was conducted to analyse soil microbial biodiversity at logged over forest on mineral soil before development to oil palm plantation, by using denaturing gradient gel electrophoresis combined with 16S rDNA polymerase chain reaction (PCR-DGGE). The average number of bands from PCR-DGGE profiles indicated strip 2 was significantly less diversified than the rest of the sites at α=0.05. Shannon-Weaver biodiversity index and Berger-Parker Dominance Index, showed highest diversity in area cultivable for oil palm, followed by the biodiversity strip areas. Bacterial communities were dominated by unclassified bacteria, Acidobacteria, Actinobacteria and α-Proteobacteria groups in all types of forest soils. Acidobacteria group was absent in strip 3 where the soil pH was least acidic. Common species found for all sites were, uncultured Acidobacteria bacterium (Acidobacteria), uncultured Actinobacterium clones (Actinobacteria) and uncultured Rhodoplanes sp. (α-Proteobacteria).