INTRODUCTIONBronchial colonisation is frequently reported in patients with lung cancer. These colonisations could influence patient therapeutic management and prognosis. The aim of our study is refine incidence and nature of bronchial colonisations in patients presenting with lung cancer.METHODSThree hundred and eighty-eight patients with lung cancer underwent a flexible bronchoscopy at the time of diagnosis. Among them, 216 patients had a bacteriological, mycobacteriological and fungal investigation. Type and frequency of these colonisations were analyzed.RESULTSPotential pathogens were found in 39.8% of samples, including mainly 39.8% of Gram-negative bacilli (Haemophilus influenzae, Enterobacter sp., Escherichia coli). In addition, we found 0.9% of mycobacteria and 13.9% of Candida albicans. Among these 216 patients where microbiological analysis was performed, patient features and tumor stage were not significantly correlated to microbial colonisation.CONCLUSIONSColonisation of airways is frequently reported when a lung cancer is diagnosed. Our data suggest that bronchial colonisation should be prospectively collected due to its potential interest in the management of lung cancer patients.