BRFSS is a state-based, random-digit–dialed telephone survey of the noninstitutionalized U.S. civilian population aged ≥18 years. The survey collects information on health risk behaviors, preventive health practices, health-care access, and disease status.* In 2005, the Asthma Call-Back Survey (ACBS)† was pilot tested in three states and has been conducted every year since. ACBS collects detailed information on asthma, including data on asthma symptoms, health-care utilization, medication use, knowledge of asthma, cost of asthma care, work-related asthma, comorbid conditions, and complementary and alternative medicine use for asthma. BRFSS respondents are eligible to participate in ACBS if they answer “yes” to the question, “Have you ever been told by a doctor, nurse, or other health professional that you had asthma?” Those who agree are contacted to participate in ACBS within 2 weeks of the BRFSS completion date. Data from BRFSS and ACBS for 2006–2009 from 38 states and DC are included in this analysis. The Council of American Survey and Research Organizations median response rates among the 38 states and DC ranged from 47.5% in 2007 to 51.4% in 2009 for BRFSS and from 47.2% in 2009 to 54.3% in 2007 for ACBS.