The books and documents that are today part of Foundation's library first began to be compiled after instructions were issued on December 4th, 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 “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 mainly 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 Inspector-General of Telegraphs from 1888 to 1910.
A librarian was appointed for the first time and introduced an ordering system that later 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 August 10th 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 of technical and cultural information within the company as a whole.