OBJECTIVES: Excessive use of short acting bronchodilators worsens asthma control. This study hypothesizes that people with no prescription drug insurance coverage tend to rely more on short acting bronchodilators (SAB) than controller drugs and consequently have higher number of Emergency Department (ED) visits. METHODS: This study utilized 2004 Medical Expenditure Panel Survey (MEPS)data. Asthma patients (ICD code: 493) were identified from the ‘medical conditions file.' Prescription drug insurance coverage and ED visits were identified from the ‘house hold component of MEPS.' Multiple logistic regression analysis was used to estimate associative risks of ED visits and SAB use among asthmatic patients with no prescription drug insurance coverage. RESULTS: A total of 14 million individuals were estimated to have asthma in U.S. in the year 2004. Amongst them 6.21 million (44.2%) did not have prescription drug coverage. A total of 3.06 million ED visits were reported by people without prescription drug coverage compared to 2.53 million ED visits by individuals having prescription drug coverage. The people with no prescription drug coverage had a noticeably higher risk of ED visit. (Odds Ratio (OR) = 1.498; 95% CI: 1.494 to 1.502). The people with no prescription drug coverage are more likely to use SAB (filled at least 10 prescriptions during the year) compared to those who had prescription drug coverage. (OR=2.544; 95% CI: 2.534 to 2.554) CONCLUSION: Asthma patients without prescription drug insurance coverage have higher number of ED visits compared to patients with insurance coverage. There is a significant association of prescription drug non-coverage and overuse of short acting bronchodilators. We conclude that the policy changes to improve access to controller drugs will reduce number of ED visits and over utilization of short acting bronchodilators.