Objective <p>The scoring system in high-resolution computed tomography (HRCT) is used to express the total abnormalities in multiple slices of a single CT. Bhalla scoring was described in 1991. In this study, we investigate the relationship between Bhalla score derived from HRCT and pulmonary function test in children with cystic fibrosis (CF).</p> Methods <p>This study was a cross-sectional analysis of children referred to the CF outpatient clinic at Children’s Medical Center Hospital from September 2017 to September 2018. The data evaluated included Bhalla score, spirometry, and throat or sputum culture.</p> Results <p>The following correlations versus Bhalla score derived from HRCT were found: FEV1 (<i>r</i> = 0.630, <i>p</i> &lt; 0.001), FVC(<i>r</i> = 0.462, <i>p</i> &lt; 0.001), FEF25-75% (<i>r</i> = 0.543, <i>p</i> &lt; 0.001), FEV1/FVC (<i>r</i> = 0.469, <i>p</i> &lt; 0.001). Patients with mucoid Pseudomonas in throat culture had significantly lower Bhalla scores than those with other types (<i>p</i> = 0.001).</p> Conclusion <p>The significant correlation between spirometry and Bhalla score derived from HRCT indicates that spirometry, which is a non-invasive method for examining the lungs of CF patients, has sufficient sensitivity to show the level of lung involvement in these patients. Additionally, mucoid Pseudomonas showed the most pronounced destructive effect in HRCT, as indicated by throat culture findings.</p>