OBJECTIVES: To determine: 1) hospitalization charges of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with lung cancer; and 2) the clinical, socio-demographic, and hospital characteristics associated with inpatient charges. METHODS: A retrospective study of the Agency for Healthcare Research and Quality (AHRQ) Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample for 2006.  An AECOPD was identified via ICD-9-CM codes in the first three diagnosis positions: 1) 491.2x identifying AECOPD; 2) 490.x-492.x and 494.x-496 identifying COPD with either pneumonia (480.x-486); or a procedure code for mechanical ventilation (93.90, 96.70-96.72) in any position.  Lung cancer in AECOPD was identified by the ICD-9-CM code 162.x.  Discharge records were included if patients ≥40 years.  Regression analyses were conducted using generalized linear model with gamma family with charges as the primary outcome.  Significance was set a priori at the 0.05 level. RESULTS: A total of 42521  hospital discharges with mean(±SD) hospitalization charge of $33436(±43647) and length of stay of 7.0(±6.8) days.  In-hospital mortality was 10.6%.  The majority was ≥65 years (73.6%), male (55.2%), had ≥4 comorbidities (62%), with Medicare as the primary payer (75.0%).  Among cases that reported race, 84.6% were white.  Age <65 year, black race (compared to white), hospitals with larger bed size, urban hospitals (compared to rural), in-hospital mortality, greater number of comorbidities, and presence of specific cormorbidities such as congestive heart failure, arrhythmias, pulmonary circulation disorders, cerebrovascular disease, and weight loss were significantly associated (p≤0.01) with increased hospitalization charges.  The Midwest and South (compared to Northeast) regions, Medicaid (compared to Medicare) and comorbidities such as depression and ischemic heart disease were significantly (p≤0.05) associated with decreased charges. CONCLUSIONS: The inpatient burden of AECOPD with lung cancer is substantial with a number of socio-demographic, hospital and clinical characteristics, particularly other comorbidities prevalent in COPD, associated with hospitalization charges.