A Catalan regional police statement said the arrests took place today in five northeastern towns, including the regional capital of Catalonia, Barcelona.
It said some 360 Mossos d'Esquadra regional police officers took part in 13 raids in one of the region's biggest operations against jihadi activity. The operation was coordinated by the National Court in Madrid.
Spain has arrested dozens of suspected jihadi militants and recruiters in recent years.
Last week, police in Catalonia arrested four members of a family, including 16-year-old twin boys who were allegedly about to travel to Syria to become jihadi fighters.