The international standardisation of Environmental Management (EM) is documented by the ISO 14000 series. Within this series a number of Environmental Management tools are treated. Therefore, it can be seen as a ‘toolbox’ which offers several options for sound Environmental Management practices in organisations. However, a number of questions remain because they are not treated by the standards themselves. Some examples are, which of the tools should be applied to what kind of Environmental Management problem or what are the synergisms and antagonisms between these tools. To illustrate the importance of a comprehensive choice and a compatible approach towards EM-tools, Life-Cycle-Assessment (ISO 14040 series) is discussed in the context of Environmental Management Systems (ISO 14001).The focus of ISO 14001 are organisations, while LCA deals with products or processes. In principle, they are not compatible, as the life-cycle approach analyses one production chain from ‘cradle to grave’ or even back to the cradle, while a management system according to ISO 14001 analyses a number of product chains from ‘gate to gate’. However, LCAs could be compiled by aggregating several ‘gate to gate’ energy and material balances of companies. LCA can assist in prioritising and achieving the objectives of an EM-System. LCA can also help to understand the environmental impact of organisations and what share of their overall environmental burden is produced ‘inside the gates’ respectively ‘outside the gates’.