This document is the User Guide for the OTAQ Fuels Program Registration (OTAQReg) online application. It describes the processes a user must follow to register; update their user profile; associate to companies as well as create, view, and edit companies. If you have any questions about the content, format, or policies for the Office of Transportation and Air Quality (OTAQ) please reference the Fuels Program website at http: //www.epa.gov/otaq/fuels/index.htm. If you have any general or technical questions related to the Central Data Exchange (CDX) you may contact any of the following: Telephone - Person-to-person telephone support is available from the CDX Help Desk 8:00 am to 6:00 pm EST. Call our toll-free line at 888-890-1995. Email - Send e-mail to Technical Support at helpdesk@epacdx.net with "Technical Support" in the Subject line. If you have any questions relating to fuels programs registration, reporting, or OTAQReg, please contact the EPA Fuels Programs and EMTS Support Line: support@epamts-support.com.