Soils of tropical forests are important to the global budgets of greenhouse gases. The Brazilian Atlantic Forest is the second largest tropical moist forest area of South America, after the vast Amazonian domain. This study aimed to investigate the emissions of Nitrous Oxide (N₂O) and Carbon Dioxide (CO₂) as well as methane (CH₄) emissions and consumptions along an altitudinal transect and the relation between these fluxes and other climatic, edaphic and biological variables (temperature, fine roots, litterfall, and soil moisture). Annual means of N₂O flux were 2.6 (±0.5), 0.9 (±0.1), and 0.7 (±0.2) ng N cm⁻² h⁻¹ at altitudes 100, 400, and 1000 m, respectively. On an annual basis, soils consumed CH₄ at all altitudes with annual means of −1.0 (±0.2), −1.8 (±0.1), and −1.6 (±0.3) mg m⁻² d⁻¹ at 100 m, 400 m and 1000 m, respectively. Although not sampled in the hottest and wettest portion of the year because of instrument malfunctions, mean fluxes of CO₂ averaged 3.6 (±0.2), 3.5 (±0.3), and 3.1 (±0.3) μmol m⁻² s⁻¹ at altitudes 100, 400 and 1000 m, respectively. N₂O fluxes were significantly influenced by soil moisture and temperature. Soil-atmosphere exchange of methane responded to changes in soil moisture. Carbon dioxide emissions were strongly influenced by soil temperature. While the temperature gradient observed at our sites is only an imperfect proxy for climate warming, our results suggest that increasing temperatures will result in increased in microbial activity with a consequent increase in soil N₂O and CO₂ emissions and soil CH₄ consumption

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