Nutrient data from a short dietary questionnaire designed for self-administration in epidemiological studies of ischaemic heart disease were compared with those from 7-day weighed dietary records obtained 2 to 6 weeks later in a sample of 119 men from the general population. For the major nutrients correlation coefficients of between 0.27 (total carbohydrate) and 0.75 (alcohol) were obtained all of which were statistically significant. In the case of alcohol over 90 per cent of the weekly intake was consumed outside the home in standard measures. In the case of other nutrients improvement in the precision of the questionnaire estimates may be obtained by direct estimates of portion sizes.