Resistance is a widespread phenomenon where arthropod populations develop the ability to avoid the lethal effects of normally fatal concentrations of one or more pesticides. As of July 20, 2007 we have cataloged 7,631 cases of resistance reported worldwide. To effectively manage resistance a central and permanent ‘data bank’ of resistance information is essential. At Michigan State University we have developed a new database system: the Arthropods Resistant to Pesticides Database (ARPD) (www.pesticideresistance.org) that has the capability for remote submitting, searching, extracting and analyzing resistance events. In the near future routine reports will include tables and figures of resistant species, pesticides, mode of action, use and classification. The database also analyzes resistance cases by IRAC mode of action. This effort was supported through a partnership between the USDA/CSREES/IPM, International Resistance Action Committee (IRAC), and Michigan State University (MSU). The web site received over 500,000 visits per year in 2005 and 2006.