OBJECTIVES: EPR-2 guidelines were developed to improve medication prescribing for patients with persistent asthma and to control acute exacerbations of asthma. In addition these guidelines also encourage physician provided asthma education. Little is known about prescribing adherence to EPR-2 guidelines. This study examined physician adherence to EPR-2 asthma medication prescribing guidelines and determine patient and physician factors associated with prescribing of asthma medications. METHODS: This study was a cross-sectional retrospective analysis of complex NAMCS physician visit survey data from 1998 through 2004. Data were extracted on all patient s with an ICD-9 code for asthma (493.XX) and reason for visit as ‘asthma'. Unit of analysis was individual patient visit. Dependent variables in analyses were specific type of drug class. Independent variables were various patient and physician factors. Logistic regression analysis was used to assess study objectives. RESULTS: Asthma patients in 2002 were 3.3 times more likely to be prescribed controller medications compared in 1998. Findings in 2004 were not significant. Elderly patients were 54% as likely to receive controller medication compared to the 35-64 year age group. Patients other than whites or African Americans are 40% as likely to receive controller asthma medication compared to whites. Physicians were 6.3 times more likely to prescribe long acting beta agonists compared to 1998. Physicians without ownership stake in their practice were 1.9 times more likely to provide asthma education to their patients compared to those who owned their practice. CONCLUSION: This study using US outpatient setting data provides evidence that physician prescribing of asthma pharmacotherapy in the US does not adequately comply with EPR-2 treatment guidelines.