Recently, world has become more conscious about the environment, changes occurring in climate and in earth in general. It started to pay more attention to the impact of the technological and industrial revolution on the ecology and human health, which resulted in directing all the new researches towards renewable energies and recycling materials. In brief, it directed architects to start using Eco-friendly building materials, construction systems, natural ventilation and lighting ?etc. This book is concerned with the existing residential buildings which have the most environmental problems in Egypt. Therefore, it aims at providing the architectural design elements to turn the existing residential buildings into ecological buildings that are one of the ways to preserve the earth for next generations.