Objective: This project aimed to determine the relationship between Asthma Control Test (ACT) score using the Arabic version, fractional exhaled nitric oxide (FENO) and Lung functions and to derive the cut-off points for the ACT score with the American Thoracic Society (ATS) recommended FENO standard levels of inflammation control.. Methodology: We recruited 59 adult asthmatics out of which 53 subjects completed the study from July 2011 to June 2012 at King Saud University, Riyadh, Saudi Arabia. FENO levels were measured by NIOX MINO (Aerocrine Solna, Sweden) and ventilatory functions were recorded by standard techniques. Results: FENO values were significantly higher in patients with an ACT score <20 (65.5 ± 35.4) compared to those patients with an ACT score ≥ 20 (27.4 ±10.5, p<0.001). Among the well-controlled group based on the ACT score criteria, 6 (25%) cases had high FENO levels, while among the poorly-controlled group, 23 (79.3%) cases had high FENO levels (Odds ratio 11.5: p<0.0001: Confidence Interval 3.16-41.72).. There was a significant negative correlation between FENO and ACT score (r=-0.581, p<0.0001). At international cutoff point of 20 sensitivity and specificity was 95.2 & 68.8 respectively. ROC showed that maximum sensitivity & specificity was observed at ACT score cut off point of 19 (90.5 and 81.2) respectively. Conclusions: FENO levels correlate negatively with ACT scores, however the relationship between FENO and lung function was not significant. A significant strong relationship between ACT score and FENO levels indicate that there is ongoing inflammatory state in patients with poor asthma control.