Background The bronchoalveolar lavage (BAL) cellular analysis is an invasive method of exploration of the lung. Its diagnostic value in interstitial lung disease (ILD) is integrated to a multi-disciplianry approach implicating clinicians, radiologists and pathologists. Aim We targeted to evaluate the diagnostic value of the BAL. Methods We reported a retrospective study about patients hospitalized for an ILD since the 1st January 2011 to the 31th December 2013. Thirty three patients were admitted in the Department of Pulmonology and the BAL analyses were studied in the Department of Pathology of the same hospital. The different cell patterns were compared to the final diagnostics. Results our study contained 4 non specific interstitial pneumonia (NSIP), 10 usual interstitial pneumoniae (UIP), 4 organizing pneumoniae (COP), 8 sarcoidosis, 2 hypersensitivity pneumonitis, 3 infectious pneumonitis, 1 lymphoma and a pulmonary adenocarcinoma. We considered positive results those that were compatible with the final diagnosis. The profile lavage was typical in 1 NSIP, 3 UIP, 3 COP, 1 hypersensitivity pneumonitis, 6 sarcoidosis, 3 infectious pneumonitis and 1 adenocarcinoma. Among the 17 cases with an atypical profile lavage, radiological features were diagnostic in 10 cases. This finding highlights the fact that 7 cases/ 33 presented simultaneously an atypical profile lavage and non specific radiological findings Conclusion Our results put emphasis on the diagnostic value of BAL especially when it is integrated to a multi-disciplinary approach. Its value in the follow up, the evaluation of the activity of the disease and the prognosis is being more and more reported.