This paper summarizes a work conducted on the isolation of microorganisms from PAH's contaminated sediments. The methodology involved two selection systems called fast route and slow route in which exposure periods and contaminant concentrations are the key determinants. The microorganisms isolated through the slow route system are more likely to be successful in degrading high molecular weight PAH's. The six strains obtained through the fast route system were able to grow on low molecular weight PAH's showing preference towards the first four EPA (Environmental Protection Agency) priority PAH's.