Archaea occupy a considerable diversity of niches encompassing extreme environments with extreme of pH, salinity and temperature that cannot be tolerated by other forms of life. Survival and colonisation requires the capacity to sense, and adapt to environmental change. In this review we consider the issues of adaptation to environmental stresses, in particular the mechanisms that might be employed by different Archaea to respond to the specific challenges of their particular niche. We lay emphasis on the strategies adopted to respond to oxidative and chemical stress. In particular, this paper reviews major key points in the generation of reactive oxygen species in Archaea, defense mechanisms and genetic responses to oxidative stress. Finally, we discuss complex biological response mechanisms to chemical damage with particular attention to detoxification from metals and drugs.