Analysis of natural ventilation in the sheds of the Sarah Network of Rehabilitation Hospitals: Case study in Salvador and Rio de Janeiro Hospitals. Marieli Azoia Lukiantchuki 1 , Edson Matsumoto 2 , Lucila Labaki 2 , Renata Camargo 2 , Rosana Caram 1 1 University of São Paulo 2 University of Campinas Corresponding email: mlukiantchuki@yahoo.com.br SUMMARY The use of natural ventilation in buildings reduces the environmental impacts and allows a higher harmony between the surroundings and the building. Besides, in tropical countries like Brazil, is a design efficient strategy to achieve thermal comfort. This is illustrated by the work of the architect João Filgueiras Lima, Lelé, which provide the rational use of electrical energy, comfort to the users and the humanization of the environments. The highlight of his architectural production are Sarah Kubitschek Network of Rehabilitation Hospitals. Thus, this paper aims to analyse the efficiency of the geometry of the Sarah Hospital’s sheds located in the cities of Salvador and Rio de Janeiro, with the purpose of highlighting it and how occurring architectural changes influence in obtaining more efficient natural ventilation. This research is based on two analysis. Firstly a qualitative analysis through the comfort passive solutions descriptions. Second, a quantitative analysis through test in the wind tunnel. The results show that the Rio de Janeiro Hospital has more efficient design solutions, and the wards of this hospital are better ventilated than the Salvador hospital. INTRODUCTION In tropical countries like Brazil, natural ventilation is highlighted as the most efficient bioclimatic strategy to achieve thermal comfort in urban and architectural environment. This natural resource is a determinant factor for the health and well-being of people, because allow a continued indoor air environment renewal, besides to reduce the electrical energy consumption. According to Jones (2001) one of the main benefits of natural ventilation is the reduction of energy consumption, because it minimizes the use of mechanic ventilation systems and air conditioning. In Brazil, the architect João Filgueiras Lima, Lelé, is well known for use in his works bioclimatic solutions, being natural ventilation one of the main aspects. His designs are real examples of sustainable architecture, and among them, is highlighted The Sarah Network of Rehabilitation Hospitals, due to their passive solutions for comfort. The Sarah Network is constituted of ten hospitals, the first being in 1980, in Brasília, and later others were built in the cities of São Luís, Salvador, Belo Horizonte, Fortaleza, Rio de Janeiro (Children’s Center), Brasília (North Lake), Macapá, Belém, and again in Rio de Janeiro (hospital) opened in the year 2009. Natural ventilation in theses hospitals is worked as one of the main aspects. It is important to highlight that as the Sarah Network is constituted of rehabilitation hospitals, designed for the treatment of patients with illnesses of the locomotor system, the use of this cooling strategy is