They had marched for a month from their hometowns before converging on the landmark Puerta del Sol Square to show their anger at the country's economic woes.
Five columns converged on the 'urban village' next to the town hall where some protestors had camped out for three weeks in May under blue plastic tarpaulins.
The marchers set off from Barcelona and Bilbao in the north, Malaga in the south, Valencia in the east and Cadiz in the south west on June 25.
Several dozen demonstrators stopped outside Prime Minister Jose Zapatero's official residence just north of Madrid to wave banners and chant slogans.
Another group halted traffic on a highway entering Madrid from the north.
During the marches to the capital, physiotherapists travelling in support vehicles helped the protesters keep their leg muscles in shape, while sympathetic paramedics treated blistered feet.
The protesters joined the 'urban village' of tents, mattresses, a kitchen, a workshop and even a pharmacy which had been set up for thousands of young people. Read More