Small enough to hook onto a keychain, USB pen drive emulates a small disk drive and allows data to be transferred easily from one device to another. The way it works is very simple. It also works very fast. Since it is a relatively newer device, manufacturers are launching it with added capabilities and higher storage power. Some of the purposes for which it can be used are discussed below.

To transport personal data

The commonest use of USB pen drive is to transport or store personal files such as documents, pictures and video. One can also store medical alert information for emergency use or as preparation against disaster.

Repairing computer

Successful usage of USB pen drive has been noticed in the PC repair field as a means to transfer recovery and antivirus software to infected PCs. It also allows a portion of the host machine's data to be archived in it in case of emergency.

System administrators’ helper

System and network administrators find USB pen drive highly handy to load them with configuration information and software used for system maintenance, troubleshooting, and recovery. Such use of this portable device makes it popular among them.

As an application carrier

USB pen drives are used to carry applications that run on the host computer without the necessity of installation. U3, backed by pen drive vendors, offers an API to pen drive-specific functions. Portableapps, a free and open-source software, has also been developed to allow U3-like functionality on non-U3 drives. airWRX is also an application framework that runs from a pen drive and turns its PC host and other nearby PCs into a multi-screen, web-like work environment.

As audio players

A number of companies make solid state digital audio players in a small form factor, essentially producing pen drives with sound output and a simple user interface. The MP3 playback function is the most popular addition to USB pen drive. Some of them also have LCD display for track browsing and audio input jack and a rechargeable battery.