The PCI bus technology implemented on a Eurocard form factor. Eurocards provide more rugged packaging and a more secure plug and socket than the standard PCI card used in desktop computers. Because Eurocards come in several sizes, CompactPCI is modular, and CompactPCI supports hot swapping.

The PICMG consortium developed CompactPCI, enabling PCI to fit into rack-mounted applications, initially used for industrial applications and later in telecom equipment. Due to enhanced backplane and connector characteristics, up to eight CompactPCI cards can be plugged into the bus rather than only three or four with PCI. See Eurocard, PCI and PICMG.