Thirteen women forced to work as prostitutes in the Spanish resort near Marbella have been freed, police say.
The victims are thought to have been brought from Bulgaria to the Costa del Sol, where they were made to work on the streets of Puerto Banus.
Police also arrested 34 suspected gang members across Europe.
In a statement, police said the Bulgarian gang had sought "total control" of the upmarket resort.
They had brought women from poor areas of Bulgaria and forced them to work as prostitutes, threatening them and their families with violence if they refused.
The women were also made to steal from their clients, some of whom may have been drugged, police said.
The arrests came almost three years after police were made aware of the prostitution ring by a woman who escaped the gang's clutches.
It was then, they said, they had discovered "an enormous international network that operated mainly in Spain and Bulgaria".
Spanish police - who worked with their Bulgarian counterparts and the European Union police agency Europol - said most of the arrests were made in Spain, with eight in Bulgaria.
They also carried out searches at properties in both countries.