Following the success of the first three meetings (Skiathos, Greece 2003, Bologna, Italy 2005, and Algarve, Portugal 2007) it has been decided to reconvene the International Conference on Sustainable Development and Planning in 2009. The Conference addresses the subjects of regional development in an integrated way as well as in accordance with the principles of sustainability. It has become apparent that planners, environmentalists, architects, engineers, policy makers and economists have to work together in order to ensure that planning and development can meet our present needs without compromising the ability of future generations. In recent years, there has been in many countries, an increase in spatial problems that has lead to planning crises. Planning problems are often connected with uneven development, deterioration of the quality of urban life and destruction of the environment. The increasing urbanisation of the world coupled with the global issues of environmental pollution, resources shortage and economic restructuring are leading to major crises. On the other hand, problems of environmental management and planning are not restricted to urban areas. Environments such as rural areas, forests, coastal regions and mountains face their own problems that require urgent solutions in order to avoid irreversible damages. The use of modern technologies in planning give us new potential to monitor and prevent environmental degradation. Effective strategies for management should consider planning and regional development, two closely related disciplines, and emphasise the demand to handle these matters in an integrated way. This conference provides a common forum for all scientists specialising in the range of subjects included within sustainable development and planning.