The usefulness of the Fractional exhaled nitric oxide (FeNO) measurements for asthma exacerbation risk prediction in asthmatic children is controversial. Fifty-seven asthmatic children who were regularly treated and had previously been stable for at least 3 months were enrolled. The asthma excerbations risk prediction by the FeNO levels and age contribution on it were investigated. As analyzed all the patients, FeNO cut off value for the significant risk of asthma exacerbation was 36.9 ppb (risk odds was 5.1 [95% C.I., 1.8 to 15.0], chi square valve = 9.0, p=0.0028). However, sensitivity and specificity were not adequate for predicting asthma exacerbation (Sensitivity, 77.8%; Specificity, 59.9%; Area under the curve [AUC], 0.674). These parameters were improved only when 6-10 year old children were assessed (FeNO threshold=39.9 ppb, risk odds=10.2 [3.1 to 33.1], chi square valve 14.8, p=0.0001); Sensitivity, 80.8%; Specificity, 71.8%; AUC, 0.758). High value of FeNO is a risk factor for the asthma exacerbation, and FeNO measurement may be more useful for asthma control in younger children than elder asthmatic children.