ABSTRACT Objectives: The presence of exercise induced bronchospasm (EIB) in children with obesity and asthma is known. The measurements of fractional exhaled nitric oxide (FeNO) level in given breath are used as an indicator of airway inflammation. It can be affected by exercise and is high in patients with asthma. It is aimed to observe how much exercise what is common cause of acute airway obstruction changes FeNO in asthmatics in this study. Methods: FeNO was measured before/after exercise in the groups of obese-asthmatic children, non-asthmatic but obese children, the normal-weight children with asthma, non-asthmatic and non-obese children between the ages of 5-18. Spirometric measurements which are frequently used in asthma were compared with FeNO levels. Results: The highest average of FeNO was seen in asthmatic-obese group, the lowest mean of FeNO was found in healthy group. Non-asthmatic but obese group had respiratory parameters increasing with exercise, while FEV1/FVC was the lowest in the group with asthma-obesity and decreased with exercise. Conclusions: There is a strong relationship among FeNO and FEV1/FVC with asthma. The highest values of FeNO found in asthma-obesity combined. It was seen that obesity increased inflamation but didn’t increase EIB.