Dichlorodiphenyltrichloroethane (DDT) is a well-known insecticide that was introduced and widely used during World War II. In total more than 4.5 million tonnes DDT have been produced. Although its use and production stopped worldwide during the 1970s, it was reintroduced in the 2000s as a malaria vector control by the World Health Organization (WHO). DDT is toxic to animals and humans. Its main characteristics are its persistence, lipophilicity, and bioaccumulative potential. DDT and its metabolites are normally determined in organisms, sediments, or soil by gas chromatography combined with either electron capture detection or, preferably, mass spectrometry. Many interlaboratory studies have been carried out on the analysis of DDT and its metabolites, and certified reference materials are now available. DDT and its metabolites have been found in air, water, sediment, and biota from all over the world. As a consequence of global fractionation and cold condensation, DDT and its metabolites accumulate in the Arctic. Since the reintroduction of DDT against malaria in Africa in 2005, monitoring of DDT compounds is again highly relevant to detect changes in environmental levels of DDT. Such monitoring is particularly needed in Africa. The first indications show an increase of DDT in humans and wildlife.