Objective This project compares the degree of tracheal collapse determined by rigid and flexible bronchoscopy in paediatric patients with tracheomalacia.Methods A total of nine patients with tracheomalacia underwent both rigid and flexible video bronchoscopy. All patients were breathing spontaneously. Cross-sectional images of the airway were processed using the ImageJ program and analysed via colour histogram mode technique in order to delineate the luminal area. Paired t-tests (conducted using Stata software version 13.0) quantified differences between rigid and flexible bronchoscopes regarding the ratios of luminal pixels at maximum airway collapse to expansion. Correlation between both techniques in terms of airway collapse to expansion ratios was determined by calculating the Pearson correlation coefficient (R).Results The difference in ratios of maximum collapse to expansion between rigid and flexible bronchoscopy was not statistically significant (p = 0.4656) and was positively correlated (R = 0.523).Conclusion The ratios suggest that rigid and flexible bronchoscopy are equally efficacious in assessing tracheomalacia severity, and may be used interchangeably in a clinical setting.