Background: The respiratory system changes with age and understanding these changes may help detect and prevent respiratory dysfunctions in the elderly. In addition, although the influence of smoking on lung function is well known, its influence on lung function and mechanics of elderly are unknown. Impulse oscillometry system (IOS) is a technique for measurements of lung mechanics, which don’t need patient effort and a minimal collaboration, beyond to reflect more precisely airway resistance/obstruction and lung tissue elastance than spirometric measurements. Aims: Thus, the present study aimed to investigate whether IOS could be or not be sensible enough to differentiate the effects of smoking in the pulmonary response of non-smokers from smokers’ elderlies. Methods: The present study compared 30 elderlies never smokers (70,96 ± 6,61) with 30 elderlies’ current smokers (69,96 ± 5,94 years old and 35,33 ± 24,93/packs/year tobacco load), without asthma or any other pulmonary disease in terms of lung function and mechanics. Results: The following differences between elderly never smokers versus smokers for spirometric values were found (FVC p<0.02; FEV1 p<0.04; FEV1/FVC p<0.04; PEF p<0.01; MEF25% p<0.02; MEF50% p<0.02; MEF75% p<0.01, IVC p<0.01) and for oscilometric values (Z5hz p<0.03; R5Hz 0.01; R20Hz p<0.04; X5Hz p<0.02), while RFres and R5Hz-R20Hz did not present differences (p>0.05). Conclusions: Impulse oscilometry can detect small airway resistance/obstruction to better differentiate the functional pulmonary alterations among never smokers from smokers’ elderlies.