Background: Impulse oscillometry can serve as a useful method in detecting initial airway changes from smoking. It is easy to use and could be good at finding small airway disease, making it something researchers are studying for use in COPD. Methods: This study, designed as a prospective comparative analysis, was conducted at a tertiary care hospital using consecutive sampling for participant recruitment. Sixty participants were enrolled and categorized into two groups of 30 each: smokers and n