The aim of the study was to determine the possibility of reducing greenhouse gas emissions in the life cycle of biofules as a result of the use DNDC model for estimating nitrous oxide. The studies showed that the replacement field N2 O emission estimates by the IPCC methodology with more accurate estimates of the emissions derived from the model DNDC, increases emission reductions by 3-15%. It is a costless way to obtain greater reductions of GHG emissions in the life cycle (LCA) of bioethanol produced from wheat and corn and biodiesel produced from oilseed rape