Recent research suggests that the diet consumed in, or shortly before, pregnancy can potentially lead to maldevelopment and diseases in the offspring, which may become apparent at any time from the embryonic stage until old age. For example, maternal diet may affect the chance of twinning (and associated complications), malformation risk, brain development, and the offspring's fecundity and risk of contracting cardiovascular diseases and cancer in adult life. Prospectively designed longitudinal studies with sufficient size and data quality are much needed to substantiate or refute these hypotheses. At present, the Danish National Birth Cohort is likely to be the largest epidemiological database containing extensive information on maternal dietary exposures. By October 2002, 100 000 women had been recruited in early pregnancy, for long-term follow-up of themselves and their offspring. The present paper details the information available in the database on early nutritional exposures with emphasis on maternal dietary intake. We also present distributions of selected nutritional exposures.