BITNET was a cooperative USA university computer network founded in 1981 by Ira Fuchs at the City University of New York (CUNY) and Greydon Freeman at Yale University. The first network link was between CUNY and Yale.

The requirements for a college or university to join BITNET were simple:

From a technical point of view, BITNET differed from the Internet in that it was a point-to-point "store and forward" network. That is, email messages and files were transmitted in their entirety from one server to the next until reaching their destination. From this perspective, BITNET was more like Usenet.

BITNET came to mean "Because It's Time Network", although the original meaning was "Because It's There Network".

Bitnet's NJE (Network Job Entry) network protocols, called RSCS, were used for the huge IBM internal network known as VNET. BITNET links originally ran at 9600 baud. The BITNET protocols were eventually ported to non-IBM mainframe operating systems, and became particularly widely implemented under VAX/VMS in addition to DECnet.