By CIARAN GILES, Associated Press
A post-mortem showed Gately, 33, an Irishman, died as a result of a pulmonary edema, or fluid in the lungs, the Balearic Islands Superior Justice Tribunal said in a statement.
"The signer of the British group Boyzone died from natural causes, owing to an 'acute pulmonary edema'," the court statement said.
"The autopsy carried out this morning showed there were no signs of violence to the body," it said, adding that Gately's remains could now be flown home.
Gately was found dead on Saturday in a house near Port d'Andratx on the western tip of Mallorca. The singer had gone to Mallorca with his partner Andrew Cowles. The two were wed in a civil union in 2006.
The court said tissue samples from the singer's body would be sent to a laboratory in Barcelona for further analysis, and that unless information contradicting the autopsy result emerged, the investigation would be closed.
The court said Cowles gave a statement at the court in the Mallorca capital of Palma on Tuesday. Other witnesses were also expected to give statements.
Spanish news reports said the two had been out drinking and that the singer had later choked on his own vomit.
Spanish police said they were called to the scene on Saturday afternoon.
The house, situated on an exclusive tree-lined seafront street, overlooks a rocky bay reputed to have some of the best sunset views on Spain's favorite holiday island.
The four other members of the band flew to Mallorca following news of the death.
Boyzone was one of the biggest acts to come out of Ireland in the 1990s. The group was a major hitmaker in Britain and Ireland in the 1990s and announced a comeback tour at the end of last year.
Gately also released several solo singles and appeared in stage musicals. He made headlines when he announced he was gay a decade ago.
News of his death shocked the British and Irish pop world.
Elton John said Sunday that he and his partner, David Furnish, were "stunned by this tragedy."