The workers left the Irving Shipyard just before 9 a.m. AT on Thursday and made their way down Barrington Street in downtown Halifax, blocking traffic in both directions.
They told CBC News they're upset by the death of a co-worker and they blame bullying by management at the yard.
Protesters said the dead worker, who had about 30 years of experience, was suspended for complaining about scaffolding safety.
Flags at the yard are flying at half-mast.
The workers said they had permission to walk off the job and plan to march to the Nova Scotia legislature, which opens Thursday for the fall session.