High air temperatures can affect human health and lead to additional deaths even under current climatic conditions. Heatwaves occur infrequently in Europe and can significantly affect human health, as witnessed in summer 2003.This report reviews current knowledge about the effects of heat-waves, including the physiological aspects of heat illness and epidemiological studies on excess mortality,and makes recommendations for preventive action.Measures for reducing heatrelated mortality and morbidity include heat health warning systems and appropriate urban planning and housing design. More heat health warnings systems need to be implemented in European countries. This requires good coordination between health and meteorological agencies and the development of appropriate targeted advice and intervention measures. More long-term planning is required to alter urban bioclimates and reduce urban heat islands in summer. Appropriate building design should keep indoor temperatures comfortable without using energy-intensive space cooling. As heat-waves are likely to increase in frequency because of global climate change, the most effective , measures and policies to protect the health of vulnerable Europeans need to be developed and evaluated.