The International Atomic Energy Agency (IAEA) is responsible for preventing the proliferation of nuclear weapons by detecting early the misuse of nuclear material or technology, and by certifying that States are honouring their safeguards obligations. The analysis of environmental samples taken by IAEA inspectors during inspections is a powerful tool for nuclear safeguards. This tool was implemented in 1996, after a successful application in Iraq, when a clandestine nuclear weapons program was discovered. The science involved in this type of analysis depends on highly sensitive and selective analytical measurements for detecting traces of nuclear materials collected in the nuclear facility???s ???environment???. The purposes of this article are to draw attention to the relevance of this subject in order to address a significant global problem and to present what have been developed in Brazil. Through compatible results with certified standards and IAEA requirements, Brazil has already demonstrated the potential of measuring the amount and isotopic composition of uranium and plutonium at the levels expected in typical environmental samples. Finally, this work suggests the necessary measurements to implement a reliable and consistent environmental samples program for nuclear safeguards in Brazil.