Spanish travel industry association Exceltur said that about 300,000 homes are offered for short-term rental in the country's 20 largest cities, with some 389,779 rooms managed by hotels.
Exceltur, which groups together major Spanish hotel chains, travel agents, tour operators and airlines, is lobbying for a new law to regulate short-term rental platforms such as such as Airbnb, describing the situation as "out of control".
Renting to tourists is twice as profitable as offering long-term rentals to residents, the Exceltur study showed.
In Spain, short-term rentals are also cheaper, on average, than hotels.
These include forcing platforms to verify that individual hosts are properly registered as tourist accommodation providers, with official permission to operate.