The fraction of exhaled nitric oxide (FeNO) is elevated in asthmatics compared to normal subjects. Many studies have demonstrated that FeNO correlates with other markers of airway inflammation. The purpose of this study was to assess the clinical utility of routine monitoring of FeNO in determining its ability to predict future asthma exacerbations compared with other standard clinical measures of spirometry, peak flows, quality of life score, medication usage, and symptoms. A convenience sample of 22 patients with moderate and severe-persistent asthma in the University of New Mexico Adult Asthma Clinic were evaluated during a routine clinic visit and then noted whether they had an exacerbation within 2 weeks of the initial appointment. Those with an exacerbation had a higher mean FeNO (29.67 ppb +/- 14.48) compared to those who did not (12.92 ppb +/- 5.17), p = 0.002. A nominal logistic regression model to determine those variables that predict asthma exacerbation found that FeNO was the only significant predictor, p = 0.03. Thus, FeNO appears to be a clinically useful tool to assess disease control in this population.