The expansion of the urban population has contributed to the formation of urban agglomerates; whose spatial morphology favors the formation of heat islands. The installation of Green Roofs (GR) is a strategy that can be applied to mitigate the effects of this phenomenon, especially in regions lacking vegetation cover. The objective of this paper is to evaluate, through Computational Fluid Dynamics (CFD), the potential to reduce the internal temperature of a building located in the city of Rio de Janeiro, Brazil. The temperatures of the inner surface of the roof were measured in two buildings, one with GR and one without GR. This information was used as input data into Solidworks software to simulate the heat distribution inside the building. Results indicated that the temperature was reduced by about 2°C in the building with GR, proving the technology's effectiveness, notably in the hottest months of the year.