Protection of the environment can be regarded as representing a substantial cost to business. However, it is typically considered from the point of view of effect on company profitability, rather than its relative importance to human kind. This paper estimates the value of Scotland's natural environment by applying the methodology developed by Costanza et al (1997a and b) for estimation of the value of the earth's ecosystem services. Ecosystem services provide the vital functions to support life on Earth, such as flows of materials and energy. Since the study's publication, further research has sought to apply this global methodology to a regional and national level (for example Loomis et al, 2000, Farber and Griner, 2000 and Stevens et al, 2000). The value derived for Scotland provides a useful context for understanding the scale and importance of Scotland's natural habitats and it helps to reinforce the message that the environment is central to human welfare (Williams et al, 2003). The valuation of ecosystem services in monetary terms provokes theoretical, practical and philosophical arguments. This paper does not seek to revisit in depth these debates; rather the valuation should be taken as a starting point for setting the importance of Scotland's ecosystems in an interesting perspective. A recent edition of the journal Ecological Economics (Costanza and Farber, 2002) was devoted to considering some of these issues and providing many avenues for further exploration.