Whistling and jeering workers from sectors ranging from education to refineries joined Tuesday's march and chanted "thieves! thieves!" in a protest aimed at lawmakers.
Petru Dandea, deputy leader of union Cartel Alfa, says workers want conditions comparable with colleagues in Western Europe.
He says just 15 percent of Romania's 5 million labor force enjoy decent working conditions.
Four trade unions who organized the protest want a minimum monthly salary of 900 lei ($310). It is currently 540 lei ($186).