Forty-one people of at least five nationalities were arrested. A boat, two planes and more than 40 luxury cars were also seized in the raid which went ahead after 10 months of investigation, officials said. Spanish, French, Finnish, Russian and Ukrainian nationals were among those arrested.
The group is suspected of laundering more than $300m (£155m) for gangs involved in murder, drug trafficking, arms dealing and prostitution.
Spanish authorities said they suspected some of the cash was illegally siphoned from Russian oil company Yukos.
Interpol and Europol were both involved in the joint Spanish-Russian operation, nicknamed White Whale.
The Spanish interior ministry described it as its biggest investigation.
Large sums are thought to have been diverted from Yukos to a Dutch company and then to one of its Spanish branches, the ministry said.
Company spokesman Alexander Shadrin denied all wrongdoing in an interview with Moscow Radio, Russia's Interfax news agency reported.
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