Background Studies of children's blood lipid profiles in relation to asthma are few, and the results are ambiguous. Objective We sought to examine whether the lipid profile is associated with concurrent asthma, altered lung function, and allergic sensitization in children. Methods High-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglyceride levels were measured at ages 5 to 7 years in the Copenhagen Prospective Studies on Asthma in Childhood2000 at-risk birth cohort. Asthma and allergic rhinitis were diagnosed based on predefined algorithms at age 7 years along with assessments of lung function, bronchial responsiveness, fraction of exhaled nitric oxide (Feno), and allergic sensitization. Associations between lipid levels and clinical outcomes were adjusted for sex, passive smoking, and body mass index. Results High levels of low-density lipoprotein cholesterol were associated with concurrent asthma (adjusted odds ratio [aOR], 1.93; 95% CI, 1.06-3.55; P =.03) and airway obstruction: 50% of forced expiratory flow (aβ coefficient, -0.13 L/s; 95% CI, -0.24 to -0.03 L/s; P =.01) and specific airway resistance (aβ coefficient, 0.06 kPa/s; 95% CI, 0.00-0.11 kPa/s; P =.05). High levels of high-density lipoprotein cholesterol were associated with improved specific airway resistance (aβ coefficient, -0.11 kPa/s; 95% CI, -0.21 to -0.02; P =.02), decreased bronchial responsiveness (aβ coefficient, 0.53 log-μmol; 95% CI, 0.00-1.60 log-μmol; P =.05), decreased risk of aeroallergen sensitization (aOR, 0.27; 95% CI, 0.01-0.70; P =.01), and a trend of reduced Feno levels (aβ coefficient, -0.22 log-ppb; 95% CI, -0.50 to 0.01 log-ppb; P =.06). High triglyceride levels were associated with aeroallergen sensitization (aOR, 2.01; 95% CI, 1.14-3.56; P =.02) and a trend of increased Feno levels (aβ coefficient, 0.14 log-ppb; 95% CI, -0.02 to 0.30 log-ppb; P =.08). Conclusion The blood lipid profile is associated with asthma, airway obstruction, bronchial responsiveness, and aeroallergen sensitization in 7-year-old children. These findings suggest that asthma and allergy are systemic disorders with commonalities with other chronic inflammatory disorders.