It was refounded as Batasuna in 2001 and subsequently outlawed by the Spanish Supreme Court for being considered the political wing of the separatist group Euskadi Ta Askatasuna (ETA).

The party was founded in April 1978 as Herri Batasuna, a coalition of leftist nationalist political groups initially brought together to advocate for "No" in the referendum to be held that year on the Spanish constitution.

Herri Batasuna's founding convention was held in Lekeitio, home of Santiago Brouard, who was then the leader of HASI (Herriko Alderdi Sozialista Iraultzailea or Revolutionary Socialist People's Party).

The same happened in 1980 in the first elections to the Basque Parliament, in which HB stood as a second political force, with 151,636 votes (16.55%), winning 11 seats.

Another well-known Herri Batasuna leader, Josu Muguruza, was also killed by members of the neo-fascist Bases Autónomas in 1989, while he was in a hotel in Madrid.