Two different methods for Life Cycle Inventory (LCI) applied to the dairy industry was performed at two dairies. In the simplified method, total environmental loads from a dairy was registred and allocated to liquid milk. Energy and emissions are measured for each process step for the detailed method. Both methods have advantages and disadvantages. The simplified method captures all energy and emissions of dairy processing, but treats the dairy as a 'black box'. The energy consumption was found to be 1,27 MJ/l and 2,55 MJ/l for the two dairies. By use of the detailed method it is easy to 'loose' information, and it is very time consuming. The energy consumption was lower than for the simplified method. The environmental loads can on the other hand be divided on the different process steps. The main conclusion is that choice of method depends on the purpose of the LCA-study.