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Abstract. According to data from the Brazilian Institute of Geography and Statistics (IBGE), in 2016, 39.5 billion eggs were produced. This production is attributed to the genetic improvement of laying hens, balanced diets and also to the accommodation of these hens in vertical systems. Consequently, this type of production causes a high rate of manure per area. As environmental problems associated with manure, we have the eutrophication of lakes and rivers, soils acidification, and the increase of greenhouse gas emissions. The temperature of environment and the metabolizable energy levels in diet may influence the rate of nitrogen excretion by laying hens. The nitrogen content in the laying hens manure was evaluated during the posture peak. Four climatic chambers were used; Chamber 01 was set at 20°C for 24 hours a day (thermal comfort - control). It is known that elevated temperatures cause higher concentrations of ammonia in the blood of the birds and may provide higher excretions of uric acid, so in Chambers 02, 03 and 04, the animals were subjected to 12 hours of heat stress (25°C, 30°C and 35°C respectively), and 12 hours in 20°C, comfort. Also, the metabolizable energy levels in ration was varied equal to 2700, 2800, 2900 and 3000 kcal/kg. It was concluded that the ambient temperature exerts a positive influence on the nitrogen excretion by hens, which leads to a higher ammonia emission potential to atmosphere. There was no influence of the metabolizable energy levels on excretion of this nutrient.