OBJECTIVES: Depression is a common co-morbid condition in patients with asthma and is associated with worsening of asthma outcomes. Increased symptom burden increases health care utilization and may lead to increased health care expenditures. The purpose of this study was to assess whether individuals with asthma and co-morbid depressive disorders have higher health care expenditures compared to individuals with asthma alone. METHODS: Two cohorts of patients with or without co-morbid depression were formed from the 2009 Medical Expenditure Panel Survey (MEPS). Propensity score (PS) matching technique was used to balance the cohorts on various parameters such as demographic information, insurance status. Patients with co-morbid depression were matched to patients without co-morbid depression on the logit of propensity score using calipers of width equal to 0.2 of the standard deviation of the logit of the propensity score. Difference in the health care expenditure of patients with co-morbid depression and those with asthma alone was calculated using the independent sample t test. RESULTS: Of the total 29,282 survey respondents, 8.1% (n=2,375) were asthmatic. The prevalence of co-morbid depression in asthma patients (12.33%, n=293) was comparatively higher than the prevalence of depression (7.55%, n=2,212) in the rest of the survey population. The total average health care expenditure of asthmatic patients with co-morbid depression ($15,427.33 ) was significantly higher than the health care expenditure of matched asthma patients without depression ($10,243.80)  (p= 0.02). CONCLUSIONS: Asthmatic individuals with co-morbid depression have higher health care expenditures compared to individuals with asthma alone, even after adjusting for differences in demographic information and insurance status. Further research is required to investigate the causal relationship between increase in health care expenditure of asthmatic patients with co-morbid depression.