<b>Aim: </b>To evaluate the relationships between sputum and bronchoalveolar lavage (BAL) cellular and bacterial findings and severity of exacerbation of chronic obstructive pulmonary disease (ECOPD).<br />
<b>Patients & methods: </b>A cross-section study was conducted on 307 patients with ECOPD. They underwent sputum and BAL inflammatory cell count and bacterial culture.<br />
<b>Results:</b> Patients with severe ECOPD have significantly higher neutrophils percentage (neut.%), lower lymphocytes percentage (lymph.%), lower eosinophils percentage (eosin.%) and higher neutrophil/lymphocyte ratio (NLR) as compared to patients with mild ECOPD. It was also shown that patients with severe ECOPD had significantly higher BAL neut.%, lower lymph.%, lower eosin.%, and higher NLR as compared to the other two subgroups. Also, patients with severe ECOPD have significantly higher frequency of cases with monomicrobial (71.30% vs. 36.10%) and polymicrobial (21.25% vs. 2.10%) growths in comparison to patients with mild ECOPD.<br />
<b>Conclusions: </b>Cellular and bacterial findings in sputum and BAL are related to severity of ECOPD.