Thousands of students marched in downtown Sofia on Sunday to complain that Bulgaria was still not stable, prosperous or well governed, exactly 24 years after the end of communist rule.
The current Socialist-led government only took office in May after the previous one was brought down by popular protests, but is already under pressure from daily demonstrations alleging corrupt ties with business groups.
Last week the deputy leader of the MRF party, a junior partner in the ruling coalition, quit shortly before prosecutors announced they were investigating him for tax fraud and money laundering. The politician, Hristo Biserov, has not commented on the allegations.
Sunday's "March of Justice", the latest in a series of student protests including sit-ins at universities, called for the government to resign.
University professors and teachers issued a statement condemning the "lies and 'tycoonisation' of the political and social environment".
The protests are supported by 60 percent of Bulgarians, according to a poll by the independent Alpha Research.
One banner read "Your time is up! 24 years of false transition is enough", accusing all the governments since communist dictator Todor Zhivkov was toppled on Nov. 10, 1989, of failing to reform politics and lay the foundations for steady economic growth.
Membership of the European Union has brought prosperity to many, but has also encouraged young people to emigrate, leaving behind an ever older and poorer population, while the failure to entrench strict rule of law and combat graft has deterred the investment Bulgaria desperately needs.
The average monthly wage is the lowest in the EU at just 400 euros ($530) and the average pension just 130 euros.
Since the end of communism, the birth rate has fallen, the mortality rate has risen, and the population has plunged from 8.98 million in 1988 to 7.32 million in 2011.