Hundreds of people marched from Herald Square to Union Square Thursday in what they called a "show of unity" for the labor movement.
The AFL-CIO formed the march "for everyone who is frustrated and worried about the growing disparity in this country," organizers said.
The union workers carried signs saying "workers' rights are human rights" and "save the middle class."
They were also joined by Occupy Wall Street activists.
VIDEO: Best of Wall Street Protests
One participant said the two causes are linked.
"We're all saying the same thing -- workers, union people, Occupy Wall Street are all saying the same thing," said Jeff Eichler. "This country has to have economic justice. This country has to have fairness. And this has to change and this is important for the election that's coming up."
Marchers included members of Local 32BJ of the Service Employees International Union which represent cleaners at more than 1,500 New York City office buildings. Earlier, the union voted to authorize a possible strike. The union's current contract expires Dec. 31.
Earlier in the day, several protesters calling for more funding to fight AIDS were arrested after forming a human chain near City Hall.
The protesters were part of a larger group of about 100 people who marched from Zuccotti Park to City Hall.
About half a dozen of them were arrested after chaining themselves together and lying flat on the pavement.
Raw Video: Arrests, Chaos as Protesters Swarm Wall Street
Police pushed them to the side of the road so that blocked traffic could pass through.
Protesters want Mayor Bloomberg and members of Congress to institute taxes on Wall Street trade to pay for AIDS treatment.