About 761 people were injured in disturbances across Catalonia on Sunday, the regional government said.
Riot policemen clashed with people who had gathered for a banned referendum on the region’s independence from Spain.
Police used force to try to stop the voting in line with the Spanish government’s pledge to stop the poll that was declared illegal by the country’s constitutional court.
Police officers prevented some people from voting, and seized ballot papers and boxes at polling stations.
In Barcelona, the regional capital, police used batons and fired rubber bullets during pro-referendum protests.
Speaking soon after the polls closed at 20:00 local time (18:00 GMT), Spanish Prime Minister Mariano Rajoy said Catalans had been fooled into taking part in an illegal vote.
Rajoy however risks international backlash for using force against his people in the quest for self determination.