A Rolodex is a rotating file device used to store business contact information (the name is a portmanteau of Rolling and Index). The Rolodex holds specially shaped index cards; the user writes the contact information for one person or company on each card. Many users avoid the effort of writing by taping the contact's business card directly to the Rolodex index card. Some companies have produced business cards in the shape of Rolodex cards, as a marketing gimmick.

The Rolodex's history is murky, but it was either invented by Arnold Neustadter , Alfred Neustadter , or Irving Fisher. Rolodex is in fact a registered trademark of the Eldon company [1], though it is often used generically. Rolodexes are still common, despite many computer applications that perform the same function.