Introduction: The rising trend in allergic diseases has occurred in parallel with an increasing prevalence in obesity, and suggesting a possible association. The increased body mass has numerous health consequences, including an impairment function of the respiratory system. The associations between eating habits and hypersensitivity to allergens have not been clarified sufficiently. Aim: to evaluate pulmonary function, nutritional status, eating habits and risk factors of obesity in children and adolescents with allergic rhinitis. Material and Methods: The study was performed in 106 children with allergic rhinitis (mean age 12.1+/-3.4; M/F 60/46) from the Department of Allergology. 43 (40.6%) of children presented only allergic rhinitis and in 63 (59.4%) additionally diagnosed with asthma bronchiale. Clinical data, detailed interview about allergies, assessment of pulmonary function and nutritional status, allergy skin test (Allergopharma) and spirometry (Jaeger) were evaluated. Nutritional habits were assessed by a food frequency questionnaire. The statistical analysis was done using the program Statistica v 10.0. Results: In the study group the mean centile of BMI was 49.4; underweight presented 25.4% of children, 55.6 % normal BMI and 18.8 % presented overweight or obesity. Multiple regression analysis showed a significant (adjusted R-squared: 0.97; p<0.05) association between high BMI and snacking between meals and low physical activity. No statistical association between the severity of diseases and BMI or body composition was observed. Conclusions: 1. The prevalence of excess body mass in the study group reached 13.5%. Eating habits were incorrect, especially obese children significantly more frequently ate snacks between meals than children with normal body weight. 2. Among the studied group of children and adolescents with allergic rhinitis and asthma bronchiale, the significant risk factors of obesity were snacking and low physical activity.