Paleozoic sedimentary deposits are exposed in several locations on Peninsular Malaysia and may contain all the elements of a hydrocarbon system. A research project aimed at documenting these Paleozoic deposits is currently carried out at Universiti Teknologi PETRONAS (UTP). Initial observations, mainly in the Kinta Valley, suggest the presence of source rocks, reservoirs and seals within the Paleozoic interval. The limestone hills of the Kinta Valley were the initial focus of this research project. The hills are remnants of extensive limestone beds, which are part of a very large Paleozoic carbonate complex that covered large parts of South-east Asia. The limestone beds are interbedded with sandstone, siltstone and carbonaceous shale over a thickness of up to 3000 m. Several layers of black carbonaceous shale, rich in organic matter are part of the clastic sequences and could constitute potential source rocks. Clay and shale layers within the clastic sequences will act as intraformational seals whereas the base Tertiary unconformity may have regional sealing capacity. The carbonate and the clastic sequences contain potential reservoir intervals, either as sandstone layers or shallow marine limestones. An analysis of the limestone hills of the Kinta Valley has led to a schematic palaeogeographic reconstruction of the Permian carbonate complex that suggests that reservoirs could be found in the eastern part and off the eastern coast of Peninsular Malaysia. Outcrops in eastern Peninsular Malaysia confirm the presence of a shallow marine platform, with potential reservoir horizons, that probably extended eastwards, far into the China Sea.