The STUC challenged the SNP on Wednesday over plans to cut corporation tax if the party wins a vote for an independent Scotland.
Congress called on the Scottish people to "organise, agitate and educate around a distinctive Scottish labour and socialist movement agenda" before their decision on the future of Scotland in 2014.
Unite union Scottish secretary Pat Rafferty said the referendum would be "arguably the most important event" in Scotland's modern history.
"The eyes of the world will be on us. The STUC has a crucial role to play to ensure the people of Scotland can shape the debate and decide the outcome," he said.
GMB delegate Linda Miller said: "Scotland cannot sleep walk its way into independence.
"We need to win reform at the level where economic power rests. Economic division is not between Scotland and England - but between rich and poor."
Aslef Scottish secretary Kevin Lindsay said: "We've engaged with our members and I've been suprised by solid support we've had against independence. But Tory cuts are not the status quo we want."
Clydebank TUC delegate Tom Morrison said: "What does it mean to our people? What does it mean to our class? Constitutional change will not improve our position unless backed by struggle for democratic control of our economy.
"Economic power lies at UK level.
"There is no such thing as 'independence in Europe.' Rather than being independent, we'd be well on the way to being a colony of the developing EU superstate."
Civil Service union PCS Scottish Secretary Lynn Henderson said: "We are for tax justice, not for lowering corporation tax.
"We want properly resourced and accountable public services. We say No to privatisation and cuts and in their place we support the democratic ideas in the People's Charter."
General secretary Grahame Smith promised the STUC would work to identify and report on the full implications of an independent Scotland and the potential to increase devolved powers for the Scottish Parliament.
"Scotland's constitutional future is too important to be left to politicians. It's not about what they want the powers for - it's about what we want the powers for," he said.
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