Returns from environmental crime are comparable to those from the narcotics trade, while the risks of conviction and penalty are relatively low, providing attractive opportunities for organized criminal groups. The emerging field of environmental forensics has borrowed extensively from general forensic science to develop techniques that can be used to detect and counter the growing global problem of environmental crime. The demand for protected species places increasing pressures on endangered species of animals and plants, while the chemicals sector produces an astonishing range of novel substances that may enter and adversely affect the environment. The high costs of treating and disposing of hazardous wastes has led to a lucrative market in illicit waste disposal, much of which is also hazardous. Faced with such diverse threats to thousands of vulnerable species, conservationists have been forced to prioritize forensic capacity to protect the most severely threatened resources, and there is a clear trend toward integrated global collaboration to follow international routes of exploitation and disposal. This article provides a brief overview of the main fields of environmental forensic science, and summarizes urgent issues currently faced by practitioners.