The books and documents found today in the Foundation's library first began to be compiled after instructions were issued on 4 December 1877 by the Minister for Public Works, João Gualberto de Barros e Cunha, for the creation of a postal library. In its very first year, 400 books were added thanks to the donations of David Corazzi, an important publisher at the time.

After the emergence of the new “Organização dos Correios, Telégrafos, Telefones e Fiscalização das Indústrias Elétricas” (Post, Telegraph, Telephone and Electrical Industry Supervisory Organisation) in 1911, the library was added to from the perspective of providing support for technical training and it focused obligatorily on compiling regulations, instructions and other legislation. At this time, it received a vast collection of technical books on electrical engineering, telegraphy, telephony and electricity that had been built up by Paulo Benjamim Cabral, the Inspetor-geral dos Telégrafos (Inspector General of Telegraphs) from 1888-1910.
A librarian was appointed for the first time whose introduction of an ordering system led to the publication of an onomastic catalogue of part of the 3,500 existing volumes.

The first set of regulations governing its operations was only issued in 1920 by Decree No. 6822 of 10 August and would remain in force for several decades.

In 1978, the CTT Documentation and Information Centre was created with a central library and a decentralised network to support and respond to the needs for technical and cultural information within the company as a whole.