Taxi drivers in the Catalan capital have gone out on a 24-hour strike against the taxi app which connects passengers with private drivers.
The strike has left Barcelona's El Prat airport and main train station almost without taxis, according to regional daily La Vanguardia.
A smaller strike is also expected in Madrid, but members of the city's largest taxi union won't be taking part, and taxis were readily available in the city centre at 9am.
Tuesday's strikes are the latest salvo in an ongiong dispute between taxi drivers and Uber.
Taxi drivers are concerned about the threat to their livelihoods posed by the Uber app. But those drivers have been told by the Spanish government they will have to compete with new technologies.
The autonomous region of Catalonia in Spain recently announced plans to fine drivers using Uber as much as €6,000 ($8,000), prompting the app-makers to tell The Local that they wanted "open dialogue" with the Catalan government over the issue.