Idiopathic pulmonary fibrosis has been associated with impairedprognosis compared with other types of ILD, it is therefore important torapidly asses the likelihood of a patient having IPF.The aim of this work is to try to know if the study ofbronchoalveolar lavage cellularity in suspected cases of ILD is helpful indifferentiating various types of ILD, also to find out its relationship to theextent of disease on HRCT and the possibility that transbronchial lungbiopsy is helpful in the establishment of final diagnosis.All cases were subjected to full history taking, clinicalexamination, HRCT scan, FOB with BAL and transbronchial lungbiopsy, BAL cellular analysis including CD4/CD8 ratio.It was found that HRCT scanning of the chest has changed thediagnostic evaluation of patients with IPF.There was a significant correlation between lymphocyte anddiagnosis of various types of ILD (P-value 0.04), distribution of lesion(P-value 0.033), BAL lymphocytosis was highly suggestive of sarcoidosisand LIP. The likelihood for sarcoidosis rose with increasing CD4/CD8ratio. Also there was a significant correlation between lymphocyte andextent of the disease on HRCT (P-value 0.04), BAL lymphocytosis in IPFcases has been associated with early pathological changes(Groundglass), less honeycombing.In the group examined, study of bronchoalveolar lavage cellularityin suspected cases of ILD is helpful in narrowing the differentialdiagnostic possibilities between various types of ILD, and CD4/CD8ratio was helpful in establishing the diagnosis of sarcoidosis.Broncholaveolar lavage cellular analysis also has a good correlation withextent of disease on HRCT. Transbronchial lung biopsy is helpful in theestablishment of final diagnosis without need for open-lung biopsy.