The decision was made during the FINA's Congress in Barcelona, where delegates from 134 national federations are currently attending the World Aquatics Championships in the Spanish city.

The event will make its global debut at the 2014 World Short Course Championships at the Hamad Aquatic Centre in Doha.

"The feeling of everybody, swimmers and coaches and Technical Committee, is that this is a very interesting event with a lot of tactics involved," FINA executive director Cornel Marculescu said.

"The most important thing is that the athletes are happy and I think that is why the decision was made.

"I think it's going to be very popular with the swimmers and this is the number one criteria for me."


The format was tried out at the opening meet of the FINA World Cup in Dubai last year when 4x50 metres mixed relays were held.

It was also part of last year's European Short Course Swimming Championships in Chartres when the host country, France, won the 4x50m freestyle and the 4x50m medley.

The events will be added to the European Long Course Championships in Berlin next year.

There was also a mixed relay at the 2007 Duel in the Pool, after the World Championships in Melbourne, when Libby Lenton (now Trickett) broke a world record when racing against Michael Phelps (pictured above) on the lead-off leg of the 4x100m freestyle relay.