The Walker cohort is a database of over 48 000 birth records that has recently become available. It contains meticulously recorded details of pregnancy, labour, birth and care before discharge for babies born in hospital in Dundee, Scotland between 1952 and 1966. These babies accounted for 75% of all births in Dundee at this time. Over 34 000 (73%) of these subjects can be identified and this presents the opportunity to link this birth information with a large number of current health-outcome databases covering both primary and secondary care. Further, it allows linkage of records across siblings and over two and, in future, three generations. The number of birth records available and linkage to current databases make this a unique birth cohort with huge potential for the investigation of the fetal origins of adult disease.