Solidarity contingents converged on Dundee from across Britain and Ireland, with many trade unions and political parties visible at Saturday's march through the city.
Organised as part of the annual commemoration by the International Brigade Memorial Trust (IBMT), the march was followed by a meeting at the memorial to the Dundee volunteers in Albert Square and the unveiling of a plaque to the hitherto unknown 17th Dundonian Alan Craig by his son and IBMT president Jack Jones.
Dundee Trades Union Council secretary Mike Arnot paid tribute to all those who volunteered.
"Today, their sacrifice calls out to the present generation. The ideas of racism and fascism are again at work in our society and economic crisis is providing the soil in which they can grow," he said.
"The trade union and labour movement must steadfastly oppose every manifestation of intolerance and racial hatred."
Opening the rally in the Wellgate Theatre, former Fire Brigades Union general secretary Ken Cameron stressed the internationalist traditions of the Scottish labour movement.
"The volunteers were motivated by a passion for justice and equality, for a world without exploitation," he said.
"The fight for freedom can have no boundaries. Today, we have to pick up that baton."
For the Spanish government and people, its consul general in Scotland Federico Palomero Quez thanked "all those who gave their blood for the freedom of Spain" and quoted Robert Burns on the joint quest for a world without oppression.
Historian Daniel Gray spoke of the close link between the fight against fascism and unemployment in Britain and individual decisions to volunteer to defend the Spanish Republic.
"Of the 2,400 members of the International Brigade in Britain, 549 came from Scotland," he recalled.
"Of these, a tenth came from Dundee and many were members of the Dundee Young Communist League."
Mr Gray also spoke of the special quality of the International Brigade as an egalitarian army and the degree to which the movement was founded in local working-class communities in Britain.
The weekend's events concluded with the unveiling of a plaque in Montrose on a building that became home to 24 Basque children who were given refuge in Scotland after the bombing of Guernica.