The Communications Energy and Paperworkers Union of Canada has voted by a large majority in favour of creating the country's largest private sector union by merging with the Canadian Auto Workers.
CEP president Dave Coles said that more than 90 per cent of delegates to the national convention in Quebec City endorsed the merger.
The vote follows unanimous support by CAW delegates in August.
"Today we witnessed history being made. This isn't just a step for the labour movement, it is a step forward for progressive people in this country," Mr. Coles said at a new news conference."
He added the new union will fight aggressively against attacks on the labour movement by governments and others.
"An attack against one will be a response against all of us."
The new union would represent more than 300,000 workers across roughly 20 economic sectors.
Most of the membership would be concentrated in manufacturing, communications and transportation. But the new entity would also represent some public sector employees working in health, education and transit roles.
Unions represent some 30 per cent of the Canadian work force, according to the CAW, well above levels in the United States.
A 16-member committee of representatives from both unions unanimously urged the organizations to formally merge by 2013.
Key players have said the two groups must join forces in order to ensure protection for existing members and inject some life back into the national labour movement.
CAW president Ken Lewenza, who was recently re-elected to a new three-year term, has said it would be hard for the union to part with its name.
However, Mr. Lewenza said a new approach to organized labour is needed in light of what he called the federal government's attack on unions in recent years.
Mr. Coles has said the merger makes sense because the two unions share a similar history and have worked together in the past.