A global assessment of allergic diseases and prenatal and postnatal exposure to various environmental risk factors is needed to enable early prevention of allergic diseases. This study was designed to evaluate an inner-city urban birth cohort to identify early environmental factors associated with atopic dermatitis and food allergy, as well as the incidence of wheezing during the 1st year of life. We evaluated 501 children from the Polish Mother and Child Cohort Study (2007-2011). The children's health, socioeconomic status, and housing conditions were assessed using a questionnaire. Exposure to tobacco was assessed based on questionnaire data and cotinine measurements. Multiple regression analysis showed that parental atopy, higher paternal education, and more frequent house cleaning significantly predicted atopic dermatitis in the 1st year of life; odds ratio (OR) for the variables was 2.7 (95% CI, 1.3-1.57), 2.8 (95% CI, 1.5-5.0), and 1.8 (95% CI, 1.1-2.9), respectively. Keeping a pet at home during pregnancy increased the risk of food allergy (OR, 1.48; 95% CI, 1.02-2.16). Longer breast-feeding decreased the risk of both food allergy (OR, 0.88; 95% CI, 0.82-0.95) and atopic dermatitis (OR, 0.9; 95% CI, 0.8-0.95) in the 1st year of life. Positive association between maternal exposure to increased concentrations of particulate matter 10 and atopic dermatitis in univariate analyses was found. Atopic dermatitis/food allergy and wheezing/inhaled corticosteroid use had distinct risk factors. The risk factor profile of atopic dermatitis/food allergy in early childhood that is defined in this study support the following recommendations: (i) longer breast-feeding, (ii) avoid pets during gestation, (iii) avoid too frequent house cleaning, and (iv) living in an area with decreased traffic density. This study was a part of the clinical trial NCT01861548 registered in www.clinicaltrials.gov.