Global soils have the capacity to act as a sink for polycyclic aromatic hydrocarbons (PAHs) and subsequently as a secondary source making soil/PAH interactions important to environmental PAH levels. A number of physical, chemical and biological processes determine P AH fate in soil but microbial degradation is the most important. Biodegradation depends on bioavailability, soil organic matter, water and nutrient content, temperature and previous exposure to PAHs. Globally, environments differ and soils from different geographic regions differ in their properties and PAH concentrations. While the importance of diffuse P AH contamination of soils is widely acknowledged in literature, most studies on P AH biodegradation in soils have been conducted on soils contaminated from a P AH point source. The aims of this project were to investigate the indigenous biodegradation of PAHs in pristine soils from different geographic locations as well as what environmental factors are most significant in the development of PAH biodegradation potential in pristine soils. Pristine soils used include soils from Antarctica, Norway, UK and Tibet. Levels of PAHs in all the soils were low and properties like soil organic matter, nutrients and water content were different. P AH degrading bacteria were present in all the soils studied irrespective of low PAH concentrations. Temperature was found to affect both the rates and extents of P AH degradation in the Antarctic soils. Results also suggest that the effect of temperature on adaptation of indigenous microbes to PAH degradation might be more important than that of lack of exposure. Further works suggested include the identification of individual P AH -degrading bacteria in these background soils and investigating the effect of increasing soil P AH-contact time in low organic matter background Antarctic soils.