It has been suggested that foetal nutrition might influence the inception of wheezing and atopic disorders in childhood but specific nutrients have not been implicated. In the Avon Longitudinal Study of Parents and Children umbilical cord samples were assayed for trace elements and minerals, and mothers were asked about wheezing and eczema in their children. Associations of cord concentrations of selenium, zinc, copper, manganese, magnesium, iron, lead and mercury with wheezing at 30-42 months, with wheezing patterns defined by the presence or absence of transient infant, later onset or persistent wheezing at 0-6 months and 30-42 months, respectively (n=2,044), and with eczema at 18-30 months (n=2,173), were analysed. Cord selenium was negatively associated with persistent wheeze (adjusted odds ratio (OR) per doubling concentration: 0.67). Cord iron was negatively associated with later onset wheeze (OR: 0.86) and with eczema (OR: 0.90). Children with high cord concentrations of selenium and iron were less likely than those with low concentrations to wheeze transiently in infancy. The level of foetal exposure to selenium and iron may possibly influence the risk of wheezing and eczema in early childhood although, in view of the multiple analyses carried out, it is possible that the main findings occurred by chance.