Abstract: Polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) are commonly referred together as Adioxins.@ The quantity of dioxins released in to the environment from regulated industrial sources has significantly declined in the last 30 years due to effective pollution controls. Today, backyard burning of trash is the largest source of dioxin emissions to the US environment. Thus, dioxins/furans are largely a legacy pollution issue. The important of analyzing samples for dioxins/furans in water, soil, sediment, tissue and air has been widely introduce in environmental pollution. Persistent organic compounds dioxins and furans are persistent organic compounds that are by-products of natural and industrial processes. Dioxins are chemically stable and are found throughout the environment. They accumulate in the food chain, mainly in the fatty tissue of animals. The most studied form of dioxin is the 2, 3, 7, 8-TCDD isomer. When released into the air, dioxins can be transported long distances and as a result are found around the world. When dioxins are released into water, they tend to settle into sediments where they bio accumulate in fish and other aquatic organisms and biomagnifying in the food chain such that aquatic species have higher concentrations than plants, water, soil and sediments. There are a variety of methodologies available for the analysis of dioxins. Detection limits range from the parts per trillion to parts per quadrillion level. Dioxins/furans-low resolution methods such as SW-846 8280 (water and solids) and EPA 613 (water) are most appropriate for investigation and characterization projects. These methods are applicable to contaminated soil, water and waste and generally have detection limits that are an order of magnitude higher than their high resolution counterparts. Dioxins/furans-high resolution ultra trace level dioxin analysis is available by methods EPA 1613, SW-846 8290, method TO-9 for ambient air and methods 0023A and 23 for source emissions testing. Typically, 17 isomers are evaluated at the part per trillion to part per quadrillion level. Total homologues and/or toxic equivalency factors can also be reported. These methods are most appropriate for drinking water programs, sediment projects, source emissions testing, ambient air monitoring, risk assessments and superfund site investigations.