BackgroundObesity has been identified as a risk factor for higher prevalence of asthma and asthma-related symptoms in children. The objective of this study was to evaluate the relationship between the prevalence of asthma symptoms and obesity among school-age children in the city of Ahvaz, Iran.MethodsA total of 903 children, 7 to 11 years of age, were enrolled in this study through cluster sampling. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to identify the children who were currently suffering from asthma. Height and weight were measured and body mass index (BMI) was calculated in kg/m2. Overweight was defined as BMI greater than the age- and sex-specific 85th percentile, and obesity as BMI greater than the 95th percentile. We determined the relationship between obesity and asthma symptoms by chi-square tests.ResultsThe prevalence of wheeze ever, current wheezing, obesity, and overweight was 21.56%, 8.7%, 6.87%, and 9.5%, respectively. The current prevalence of wheezing among obese and overweight children was 68.75% and 37%, respectively, and there was a statistical association between obesity and the prevalence of current wheezing (p < 0.001), night cough (p < 0.001), and exercise-induced wheezing (p = 0.009), but obesity and overweight were not associated with eczema and allergic rhinoconjunctivitis, so it seems that the pathophysiology of asthma in obese and overweight children is not related to allergy.ConclusionThere is a strong association between asthma symptoms and both overweight and obesity in both sexes among school-age children.