Leaders in the northeastern Spanish region will set a date for the vote, a spokesman for regional head Carles Puigdemont said, bringing to a head years of court battles and political clashes with the central government over the independence movement. The vote has been flagged for after the summer.
Previous secessionist challenges in Catalonia, after the long-running independence drive began to gather more popular support during an economic crisis, were blocked by Spain's conservative government, which appealed to the Constitutional Court.
Pro-independence campaigners staged a symbolic ballot on splitting from Spain, organised by volunteers rather than government officials to get around court restrictions, in 2014, months after Scots voted to stay in the United Kingdom.
About 2 million people voted in favor of seceding in Catalonia in that non-binding ballot, though turnaround was relatively low in a populous and wealthy region that makes up around a fifth of Spain's economic output.
More legal wranglings are now likely to follow this referendum announcement, which could culminate in regional elections in Catalonia if plans to hold the vote are quashed, a central government source said.