Background: Intrauterine and early neonatal exposures─ including maternal, obstetric, and postnatal factors─ may influence the risk of atopic sensitization in offspring. However, their independent associations with inhalant and food sensitization, as distinct outcomes, remain underexplored. Methods: Serum IgE levels for six food and eight inhalant allergens were measured in 619 five-year-old children participating in the prospective Kuopio Birth Cohort (KuBiCo). Atopic sensitization was defined as IgE >0.35 kU/L and >1.0 kU/L. Data on prenatal, obstetric and neonatal factors, and breastfeeding were collected through questionnaires and hospital records. Associations between early-life exposures and atopic sensitization were assessed using ANOVA, cross-tabulation and logistic regression models. Results: Atopic sensitization was observed in 38.0% of the children─ 25.4% for inhalant allergens and 31.7% for food allergens. In multivariable analysis, Cesarean delivery was associated with a 1.4─2.2-fold increased risk of inhalant sensitization, while living on a farm during pregnancy was associated with a 70% lower risk. In contrast, food sensitization was associated with median birthweight and lower maternal weight in the first trimester. Other maternal and perinatal factors, such as maternal education, infertility treatment prior to pregnancy, gestational diabetes, hypothyroidism or preterm delivery showed no significant associations. Conclusion: Perinatal factors appear to influence atopic sensitization more against inhalant than food allergens. A range of prenatal, obstetric, and early-life factors may contribute differentially to the risks to sensitization to inhalant and food allergens. As many of these factors are potentially modifiable, further research is warranted to explore preventive strategies.