This work deals with odor emissions from biogas plants and their detection possibilities. It captures main objects of the plant and characterize them in terms of risk of odor. In the beginning, it decscribes the increasing interest in the biogas plants‘ construction, process of biogas and digestate production and also indicates problem in legislation. In the following section it explains basic objects together with main processes happening in it. It describes more in detail the problem of specifying the measures in the legislation and points out a risky operation in terms of odor in the biogas production‘s process. After accessing the current state of odor load in Slovakia it distributes various metods of odor measurement and modeling, displays their comparison and evaluates possible applicability in practise.