We explored the feasibility of using SalesGenie, a commercially available database, as a potential alternative to traditional methods of selecting controls for population-based case-control studies. An attractive feature of this particular database is that it permits a search within specific age ranges, geographic locations, and household income. Information on 1,068 cases reported to the California Cancer Registry between 2001 and 2005 was entered manually into the SalesGenie Web-based search engine. The frequency of Registry-to-SalesGenie matches was then compared with the frequency of matching the registry data to the California Department of Motor Vehicles (DMV) records. Our findings indicate that the SalesGenie database is currently less comprehensive than DMV records. Nevertheless, Web-based population data sources may provide a potential alternative for population-based studies when used in conjunction with other methods, particularly in states where DMV records are not accessible to researchers.