He studied Secondary Education in Lugo. In 1967, he started Economical Sciences, taking his degree in 1972. Since 1973, he has been working as Professor of Applied Economy, teaching the following subjects: World-wide Economical Structure, Economical Structure of Galicia, World-wide and Spanish Economical System and Public Company and Economical Regulation.
He combines his job with the political activity. In 1972, he joined the Galician Socialist Party (PSG), where he was in charge of youth and education. In 1977, he took part in the candidature of the PSG in Lugo to the Spanish Parliament in the first democratic elections. In 1978, he left the PSG and joined the PsdeG-PSOE, taking part in the Galician Socialist Collective. One year later, he was nominated as secretary of political relations. From 1980 to 1982, he held the post of general vice-secretary of the party, taking an active part in the negotiations to elaborate and, in a later stage, to modify the Galician Statute of Autonomy.
In 1981, he came first in the socialist list in Lugo for the first Galician Parliament. He continued to be a Member of Parliament during the following session 1985-1989. It was then that he was elected as President of the Economy Committee of Parliament. During the following sessions (1989-93 and 1993-87), Ceferino Díaz became a Galician Member of Parliament in A Coruña, being elected once again as President of the Economy Committee. Finally, he was a deputy at the Spanish Parliament in A Coruña and general secretary of the PsdeG-PSOE in Compostela.
His research work focussed on the field of Galician economy. He published many works concerning mainly the agrarian economy.
Publications:
-Agricultura e Capitalismo en Galicia (en Revista Galega de Estudios Agrarios nº1).
-Problemas estructurais na integración da agricultura galega na CEE (en Revista Galega de Estudios Agrarios, nº4).
-Os presupostos autonómicos (Cuadernos de Economía del Seminario de Estudios Galegos).
-Galicia na CEE (Revista Encrucillada).
-A Autopista do Atlántico (Galaxia-colectiva).
He published articles in different newspapers and magazines about economical and political themes. He also gave many lectures and took part in seminars.