Headquartered in Roanoke, Va., Advance Auto Parts, Inc., a leading automotive aftermarket retailer of parts, accessories, batteries, and maintenance items in the United States, serves both the do-it-yourself and professional installer markets. As of July 12, 2008, the Company operated 3,325 stores in 40 states, Puerto Rico, and the Virgin Islands.

http://www.advanceautoparts.com/ 

As of May 3, 2008, AutoZone sells auto and light truck parts, chemicals and accessories through 4,032 AutoZone stores in 48 states, the District of Columbia and Puerto Rico in the U.S. and 130 stores in Mexico. AutoZone is the leading retailer and a leading distributor of automotive replacement parts and accessories in the United States.

More than 80 years ago, the National Automotive Parts Association was founded to meet America’s growing need for an effective auto parts distribution system. NAPA has been the industry leader ever since and an invaluable partner In the flow of parts from manufacturers to NAPA AUTO PARTS Stores.More wholesale customers use NAPA parts than any other auto parts supplier- and 94% of do-it-yourself customers recognize the NAPA brand name.

http://www.napaonline.com/ 

O'Reilly Automotive, Inc. is one of the largest specialty retailers of automotive aftermarket parts, tools, supplies, equipment, and accessories in the United States, serving both professional installers and do-it-yourself customers. Founded in 1957 by the O'Reilly family, the Company operated 1,830 stores as of December 31, 2007. In July 2008, they acquired CSK Auto which operates 1,349 stores in 22 states.

http://www.oreillyauto.com/ 

Pep Boys has over 560 retail stores and approximately 6,000 service bays in 35 states and Puerto Rico. Along with its full-service vehicle maintenance and repair capabilities, the Company also serves the commercial auto parts delivery market and is one of the leading sellers of replacement tires in the United States.

http://www.pepboys.com/