If you are editing this page, remember that this is a directory of companies that primarily sell new parts, while the surplus page is intended for shops that sell used or salvaged parts and equipment. There is necessarily some overlap between the two. If you think a retailer sells both types of items, then it's ok to add it to both lists.

• Allied Electronics - http://www.alliedelec.com/

• Digikey (Thief River Falls, MN) - http://www.digikey.com
• Element 14 - http://us.element-14.com/
• Newark / Farnell / Element 14 are all part of the same company (Premier Farnell). The many faces of Farnell are confusing. I don't think Element 14 actually has a printed catalog. What is Element 14's online store - another interface to Newark or Farnell's catalog? Something else? I'm not sure. — jeff 01/15/2011 12:12
• Mouser - http://www.mouser.com
• Mouser is located in Mansfield, TX (near Ft. Worth), so UPS ground shipping to Austin is usually overnight. (USPS, however, still takes 2-3 days) — jeff 01/15/2011 12:04
• Newark Electronics - http://www.newark.com
• Online Components - http://www.onlinecomponents.com/
• ROHM - http://www.rohm.com/web/global/

• Jameco (San Mateo, CA) - http://www.jameco.com
  • Smaller operation with limited selection, but they tend to carry the most useful stuff, their catalog is easy to browse, and they have very good prices on some items.
  • They have a will-call counter in Belmont, CA (20 minutes from San Francisco).
• Futurlec http://www.futurlec.com
  • Thailand-based discount electronics supplier. Cheap prices, I've seen some complaints of long shipping times. — jeff 10/03/2011 16:01
• Tayda Electronics http://www.taydaelectronics.com
  • Cheap components, located in Thailand.
• dipmicro http://www.dipmicro.com
  • Canadian components store.

These are smaller companies that generally cater to the hobbyist market, although some of them are getting quite large (eg. Sparkfun).

• Adafruit (New York, NY) - http://adafruit.com
• All Electronics (Van Nuys, CA) - http://www.allelectronics.com
• Alltronics (San Martin, CA) - http://www.alltronics.com
• Dan's Small Parts and Kits (Missoula, MT) - http://www.danssmallpartsandkits.net
• Electronic Goldmine (Scottsdale, AZ) - http://www.goldmine-elec.com
• Electronix Express (Avenel, NJ) - http://elexp.com
• Evil Mad Science (Sunnyvale, CA) - http://evilmadscience.com
• Marlin P. Jones & Assoc. - http://www.mpja.com/
  • Cheap soldering stations
• NKC Electronics - http://nkcelectronics.com
• Sparkfun Electronics (Boulder, CO) - http://www.sparkfun.com
• Unicorn Electronics (Aliquippa, PA) - http://www.unicornelectronics.com/
  • Obsolete and hard to find components.
• Seeed Studio depot - http://www.seeedstudio.com/depot/
• Cute Digi - (China) http://www.cutedigi.com

• Aliexpress - (wholesale suppliers from all over the world) http://www.aliexpress.com/wholesale?SearchText=arduino&CatId=0
• DealExtreme http://www.dealextreme.com/ - Low prices on some things, some interesting and random items, shipping can take a long time.
• KaiDomain http://kaidomain.com/ - Another site like DealExtreme? I have not purchased from them.
• Add more here…

• Antique Electronic Supply (AES) - They have guitar amp parts, too.
• Fair Radio Sales - Lots of radio parts included in their extensive surplus inventory.
• http://midnightscience.com Home of the Xtal Set Society
  • New air variable tuning capacitors, galena crystal detectors, crystal radio kits, etc.
• Peebles Originals - Several varieties of variable capacitors, interesting radio kits.
• Surplus Sales of Nebraska - Huge variety of variable capacitors, trimmers (including hard to find piston types), oil-filled caps, etc.

• 4Ucon http://www.4uconnector.com

• Grainger - http://www.grainger.com
• McMaster-Carr - http://mcmaster.com

• See the list of surplus shops.
• Jameco has a will-call counter, convenient for those living in the San Francisco Bay Area.
• You-Do-It Electronics, Needham, MA - http://www.youdoitelectronics.com
• Electronics Plus, Littleton, MA - http://www.electronicsplus.com/
• JK Electronics Wesminister, CA http://jkelectronics.com/
• Marvac Costa Mesa, CA
• Creatron Inc., Toronto, ON http://www.creatroninc.com/
  • Carries a lot of SparkFun, Pololu and Adafruit stuff, can be a bit pricey.
• Sayal Electronics, Toronto and surrounding area, ON http://www.sayal.com/
  • Website is next to useless, poor selection of new semiconductors, BUT it's about the only option for a lot of people in the area.