The problem chosen for this Thesis is the challenge facing professionals working in protected areas to find ways of demonstrating that the conservation of biodiversity and its sustainable use have a fundamental relevance to the daily lives of people, including those who may never visit a protected area - and the need to emphasise the purposes of protected areas as contributing to the quality of life. The hypothesis raised is two-fold: (1) in-situ biodiversity conservation, promoted by protected areas, benefits human health, whereas human health is holistically understood as quality of life; and (2) when quality of life is improved, people's perception towards the protected area is also improved. The three key-concepts of this study - Human Ecology, Biological Diversity and Human Health - are reviewed. The concept and methods of Human Ecology, as well as the implications, history and needs for in-situ conservation of Biological Diversity are highlighted. The holistic and official definition of Human Health is reinforced, as a paradigm shift to the dominant disease-oriented approach, and its validity as a conceptual alternative for sustainable development is argued. Eight ways in which protected areas can improve human health are developed. Four of these health benefits of protected areas are briefly described and remain as anecdotal evidence, while the other four are better explored through fieldwork in Brazil, Costa Rica, Poland and Kazakstan. These health benefits of protected areas constitute a contribution to academics, decision-makers and protected-area managers interested in improving the relation between local communities and in-situ biodiversity conservation, world-wide. The example of the Integrated Conservation-Development Project (ICDP) carried-out at the Serra da Capivara National Park, Brazil, is chosen to be further scrutinised. A case-study is performed, combining qualitative and quantitative data. The village that suffers more impact - both in terms of time and intensity of contact with the conservation-development activities locally performed - is compared with a control-village. Changes in lifestyle, education levels, access to health-care, employment opportunities and health standards were evidenced by the qualitative data. The quantitative analysis suggested that the improvements in the housing conditions, water supply, storage and treatment, as well as in the perception of the villagers towards the Park and the ICDP activities were more significant in the village affected by the ICDP, than in the control village. Finally, the assessment of the research findings and the contribution of this work are summarised. What has been discovered, by pulling together the research questions; the achievements, limitations and difficulties; as well as the opportunities for further work are identified.