Rationale and Objectives: Evidence is emerging that exposure to maternal distress in early life plays a causal role in the development of childhood asthma. As much of the data is from high-risk cohorts, we undertook a birth cohort study in a complete population of children to test this association. Methods and Measurements: Using Manitoba, Canada's health care and prescription databases, this longitudinal study assessed the association between maternal distress during the first year of life and onwards, and asthma at age 7 in a 1995 birth cohort of 13,907 children. Maternal distress was defined on the basis of health care or prescription medication use for depression or anxiety. Asthma status was derived from health care and prescription records for asthma, using a definition validated by comparison to pediatric allergist diagnosis. Multiple logistic regression was employed to determine the likelihood of asthma (OR, 95% CI). Main Results: Independent of well-known asthma risk factors, our population-based study of a non high-risk cohort demonstrated an increased risk of childhood asthma (OR=1.25, 95% CI: 1.01-1.55) among children exposed to continued maternal distress from birth until age 7. Exposure to maternal depression and anxiety limited to the first year of life did not have a demonstrable association with subsequent asthma. Of interest, we observed that the risk of asthma associated with continued maternal distress was increased in children living in high versus low income households (OR=1.44, 95% CI: 1.12-1.85). Conclusions: Maternal distress in early life plays a role in the development of childhood asthma, especially if it continues beyond the postpartum period.