Mortality from coronary heart disease is decreasing in a number of Western countries, although the pattern of the decrease differs from country to country. In the UK the mortality rate from coronary heart disease has declined since 1979, whereas in the USA mortality from this disease began to fall in 1968 and has continued since that time. Of many factors suggested as reasons for the decline, diet has been implicated, particularly dietary fat intake. However, food balance information suggests little change in fat intake. A recent examination of all published studies from the USA where individual fat intake has been reported indicated that fat intake in that country has fallen steadily since the mid 1960s. The present study describes a similar compilation of all published studies from the UK giving individual fat intakes. Ninety-seven studies, representing information for 24045 individuals, were used. Studies ranged in size from two to 3581 individuals and were drawn from all regions of the UK. Most studies used 7 d weighed intakes as the method of dietary assessment. Quadratic regression equations were applied to the fat intakes from all studies over time, with each study weighted by the number of individuals surveyed. Data were also divided into 10-year periods and weighted fat intakes for each decade were calculated. Data were expressed for all studies, then subdivided into males, females, children and the elderly. Comparisons between Scotland and the South-East of England were made. Results indicate that fat represented 30% or less of dietary energy in the UK until the 1930s, when it began to rise. This rise was curtailed by rationing during and after the Second World War, after which the rise continued, reaching a plateau of about 40% energy in the late 1950s, with little change until the late 1970s. Trends were similar in all age-groups, but less change has occurred recently in Scotland compared with South-East England. These results differ from the pattern in the USA and suggest that if greater changes in mortality from coronary heart disease are to be seen in the UK a greater reduction in dietary fat intake will have to occur.