The impact noise caused by walking, falling objects or striking port is a type of noise that causes discomfort to users of residential buildings. The complaints about this type of noise are recurrent in Brazil and Portugal. The Brazilian standard Residential buildings up to five storiedperformance, ABNT NBR 15575-3 (2008) presents the minimum values of acoustical performance, including the impact sound pressure level of floors. Although this standard could be an important resource to users of the residential buildings that they felt uncomfortable, given that the value established as minimum performance level for the weighted standardized impact sound pressure level, L'nT,w, of 80 dB, at most, is high. In Portugal, the criterion for impact sound pressure level of floor is indicated by Executive Decree no. 96/2008. This paper presents the results of evaluation of performances of floors in buildings in Brazil and Portugal. The measurements of the impact sound pressure level on buildings were performed in the city of São Paulo (Brazil) and in the region of Coimbra (Portugal) using the same proceedings and measurement system. The results were compared with the performance criteria of their country and other countries and showed the difference in criteria and acoustic performance of floors between the two countries.1 2229(2008) Residential Buildings Up to Five Storied - Performance Part 1: General Requirements, , ABNT NBR 15575-1. Rio de Janeiro(2008) : Residential Buildings Up to Five Storied - Performance Part 3: Requirements for Internal Floors Systems, , ABNT NBR 15575-3. Rio de JaneiroBarry, P.J., Desempenho acústico em edifícios habitacionais (2005) Seminário Habitação: Desempenho e Inovação Tecnológica, pp. 76-83. , Instituto de Pesquisas Tecnológicas do Estado de São Paulo, IPT. São Paulo, 26-27 October(1998) Acoustics - Measurement of Sound Insulation in Buildings and of Building Elements - Part 7: Field Measurements of Impact Sound Insulation of Floors, , ISO 140-7. Genève(2003) Acoustics- Measurement of Sound Absorption in A Reverberation Room, , ISO 354. Genève(1996) Acoustics - Rating of Sound Insulation in Buildings and of Building Elements - Part 2: Impact Sound Insulation, , ISO 717-2. GenèveKoster, A., Saint-Gobain Insulation acoustical comfort classes (2007) Proceedings of the 19th International Congress O Acoustics (ICA), , Madrid, September, 2-7Mitidieri Filho, C.V., Desempenho normalizado (2004) Téchne, 86, pp. 20-23. , São Paulo: Pini, May. InterviewNeto, M.F.F., (2009) Acoustic Comfort Level: A Proposal for Residential Buildings, p. 257. , Campinas, Thesis (PhD in Civil Engineering) - School of Civil Engineering and Architecture, State University of CampinasRegulamento Dos Requisitos Acústicos Dos Edifícios, 2008 (110), pp. 3359-3372. , PORTUGAL. Executive Decree no 96/2008. Diário da República I-Série A. LisbonSalles, D., A difícil arte de viver em condomínio (2010) Revista Veja São Paulo, , Ed. Abril. Ed. 2162. 28 de abril deThaden, R., (2005) Auralization in Building Acoustics., p. 143. , These. Fakultät für Elektrotechnik und Informationstechnik der Rheinisch-Westfälischen Technischen Hochschule Aachen. AlemanhaRasmussen, B., Rindel, J.H., Concepts for evaluation of sound insulation of dwellings - From chaos to consensus? (2005) Proceedings... Forum Acusticum 2005, , Budapest