This review gathers information about the current legal requirements related to the emission of ammonia and greenhouse gases from animal housing in 21 out of the 28 EU countries and in 5 non-EU countries. Overall the review shows that most of the included countries have established substantial procedures to limit ammonia emission and practically no procedures to limit greenhouse gas emission. The review can also be seen as an introduction to the substantial initiatives and decisions taken by the EU in relation to ammonia emission from animal housing, and as a notification on the absence of corresponding initiatives and decisions in relation to greenhouse gases. An EU directive on industrial emissions from 2010 and an implementation decision from 2017 are the main general instruments to reduce ammonia emission from animal housing in the EU. These treaties put limits to ammonia emissions from installations with more than 2000 places for fattening pigs, with more than 750 places for sows and with more than 40,000 places for poultry. As an example, the upper general limit for fattening pigs is 2.6 kg ammonia per animal place per year. This review indicates that the important animal producing countries in the EU have implemented the EU requirements, and, that only a few countries with a large pig population, in relation to their geographical size, have implemented requirements that are stricter than what is required by the EU.