The SDS was officially founded on 7 December 1989 as a union of eleven political organizations, such as Ekoglasnost, Bulgarian Social Democratic Workers' Party (United) and Bulgarian Agrarian People's Union "Nikola Petkov".
民主勢力聯盟在1989年12月7日正式成立，由11個政治團體組成，如生態公開（Ekoglasnost）、保加利亞社會民主工人黨 (聯合)（Bulgarian Social Democratic Workers' Party (United)）和保加利亞「尼古拉·佩特柯夫」農業人民聯盟（Bulgarian Agrarian People's Union "Nikola Petkov"）。