He was the general secretary of CERN at its early stages when operations were still provisional, before September's 1954 official foundation.

His main scientific results were on slow neutrons in the Fermi group, and the evidence for antiproton annihilations with emulsion techniques, somewhat contemporary to its production in accelerators by Emilio Segrè and collaborators.

He also wrote historical-scientific books; for example, a biography of his friend Ettore Majorana who mysteriously disappeared.

[15] Amaldi died unexpectedly on 5 December 1989, still in full activity, while he was president of the Accademia dei Lincei, of which he had been a member since 1948.

The third Automated Transfer Vehicle of the European Space Agency bore his name,[16] so does a square on the CERN site in Meyrin.