In Britain death rates from several important causes, particularly circulatory and respiratory diseases, rise markedly during the colder winter months. This close association between temperature and mortality suggests that climate change as a result of global warming may lead to a future reduction in excess winter deaths. This paper gives a brief introductory review of the literature on the links between cold conditions and health, and statistical models are subsequently developed of the associations between temperature and monthly mortality rates for the years 1968 to 1988 for England and Wales. Other factors, particularly the occurrence of influenza epidemics, are also taken into account. Highly significant negative associations were found between temperature and death rates from all causes and from chronic bronchitis, pneumonia, ischaemic heart disease and cerebrovascular disease. The statistical models developed from this analysis were used to compare death rates for current conditions with those that might be expected to occur in a future warmer climate. The results indicate that the higher temperatures predicted for 2050 might result in nearly 9000 fewer winter deaths each year with the largest contribution being from mortality from ischaemic heart disease. However, these preliminary estimates might change when further research is able to make into account a number of additional factors affecting the relationship between mortality and climate.