There is increasing evidence that dietary factors in early life play a role in the aetiology of childhood asthma. Our objective in this analysis was to assess whether maternal dietary patterns during pregnancy, as measured by a validated food frequency questionnaire, influenced general practitioner diagnosis of asthma by the age of 3 years in the Life-ways cohort of children. General Practice follow-up records were available for 631 of 1001 singleton children, twins having been excluded (63% follow-up rate). Overall 10.4% of children had diagnosed asthma, a prevalence rate comparable with other studies. In logistic regression models, based on quartiles of intake, which adjusted for maternal lifestyle and socio-economic circumstances, relatively higher maternal fruit and vegetable intake and oily fish consumption were associated with lower risk of children developing asthma, whilst those with relatively higher spreadable fat intake had a higher risk of asthma. These findings warrant further investigation as they imply an important role for maternal diet in childhood asthma, though the confounding effect of other social and lifestyle factors should be assessed as the children get older.