A policy brief from the UCLA Center for Health Policy Research presents data by California legislative and Congressional districts on the asthma symptom rates for the more three million California children, adults and elderly who suffered from the condition in 2002. This policy brief highlights the geographic variation in asthma rates across the state for all Californians previously diagnosed with asthma that had at least one symptom in the previous year. The first of-its-kind, sub-county data in this publication are useful for policymakers, advocates and medical providers who are working to address the growing problem of asthma throughout California and within local communities. You can find a copy of the policy brief at: //www.healthpolicy.ucla.edu/pubs/publication.asp?pubID=100. Asthma prevalence rates were estimated by applying a small-area methodology to multiple data sources, including the 2001 California Health Interview Survey (CHIS 2001), 2000-2002 Current Population Surveys, and the 2000 Census.