Background: Alterations of the circadian rhythm negatively impact several aspects of the health, including the lung function. Chronic shiftwork scale classically induces alterations in the circadian rhythm. However, its effects on pulmonary immune response are unknown. Aims: To evaluate the impact of chronic alteration of circadian rhythm on pulmonary function and immune response. Methods: In this context, a 12h x 24h and 12h x 48h work scale in shiftwork scale policemen (n = 25; 38,73±6,92 years old) were compared with fixed work scale (8h/day) civil men (n = 25; 34,00±9,60 years old) who were evaluated for perceived stress, sleepiness, physical activity levels, anthropometric characteristics, sleepiness levels, lung function, pulmonary and systemic cellular and humoral immune response. Results: Policemen presented increased levels of perceived stress (p<0.0008), impaired sleepiness (p<0.04) and lung function as demonstrated by reduced FVC (p<0.053) and FEV1 (p<0.043) when compared to civil men. In addition, increased levels of exhaled nitric oxide (p<0.037) and of IL-2 (p<0.0046) in the breath condensate revealed that policemen presented chronic lung inflammation compared to civil men. Although the whole blood analysis did not showed any differences between the two groups concerning the number of leukocytes, the humoral response revealed that policemen presented increased levels of IL-2 (p<0.002) and lower levels of IL-10 (p<0.001), clearly displaying a clinical status of low grade inflammation. Conclusions: Chronic alteration of circadian rhythm in shiftwork scale policemen results in impaired lung function, beyond to impair pulmonary and systemic immune function.