There is a widespread recognition that cities, towns and villages have become increasingly dependent on motorized transport and a car-based land-use pattern. This has led to a series of unintended consequences--in particular, a lack of regular exercise, the decline of local communities and excessive greenhouse gas emissions--ith huge long-term impacts on health and wellbeing. Official policies are trying to change the trend, with much rhetoric about 'sustainable development' and 'sustainable communities'. Yet many of the decision processes that control change in the built environment have not caught up with the new agenda. This paper is concerned with the way in which new development proposals are tested for their health and sustainability credentials. It reviews the theory and practice in this field, with a particular focus on environmental impact analysis and health impact assessment. It identifies the relative strengths and weaknesses of these tools, examining the degree to which they are systematic in their approach to health and sustainability, and include all those who have a legitimate interest in the outcomes. Then a new technique--Spectrum appraisal--is presented. Spectrum is a logical and very practical process that facilitates consensus-building and creativity in decision-making. Practical applications show how the technique can be used to help ensure a healthier, more sustainable urban environment.