Around 180,000 people took to the streets in the region’s capital, hanging ballot boxes and chanting the regional anthem.
Police used batons to control the thousands marching, some of whom were waving yellow, red and blue separatist flags and chanting “October 1, no forgiving, no forgetting”.
Protestors surrounded the regional parliament building and displayed posters reading “Republic under construction”.
One year ago Catalonian residents voted to split from Spain, but the vote was not recognised as legitimate by the Spanish government.
Whilst Catalonia unilaterally declared independence, Madrid then imposed direct rule and elections later returned a regional government favouring a split with Spain.
Current polls show a relatively equal split between those who want independence for Catalonia and those who favour remaining in Spain.
Prime Minister Pedro Sanchez has ruled out any shift on the government’s fierce opposition to independence, but said he wants a dialogue about the future of the region.
Pau Benito, 22, a medical student attending the protest with friends, said he supports leaving Spain but thinks the independence movement must be cautious, so they do not alienate people.
He said: “Half of Catalonia doesn’t support independence.
“In the same way we are asking for better treatment from Spain we also need to respect those who don’t agree with us.”
Elsewhere in Catalonia yesterday, hundreds of protestors attempted to block train tracks and roads, with some laying tyres across a motorway.
These attempts were short-lived however and the protestors were quickly dispersed.
It was fairly quiet in Sant Julia de Ramis, a village where violent clashes broke out last year with riot police and citizens wishing to vote.
People queued there on Monday to re-enact the ballo, whilst regional leaders gave speeches.
Regional parliament speaker Roger Torrent said: “The first of October will be the seed of the Republic.”
On Saturday, six people were arrested in Barcelona after citizens clashed with police, as thousands were already protesting the anniversary of the infamous vote.