Yan Bhartelemy Varela swept to victory in boxing's light flyweight final, beating Atagun Yalcinkaya 21-16.
The Cuban was soon followed by talented team-mate Guillermo Rigondeaux, who got a 22-13 win over Thailand's Worapoj Petchkoom to take bantamweight gold.
And three-times champion Mario Kindelan then showed his guile to beat Briton Amir Khan in the lightweight final.
Cuba won six golds in total, but had a Sunday failure when Lorenzo Aragon lost to welterweight Bakhtiyar Artayev.
Varela recovered from a tentative start to win his country's first gold medal of Sunday.
Yalcinkaya, 17, was trying to become the youngest Olympic champion since American Floyd Patterson in 1952.
The Turk mounted a brave bid and led 4-2 after the first round, before slipping behind to cagey boxing from Varela.
Rigondeaux, meanwhile, was impressive throughout his bout exacting revenge for Cuba after one of their hopes Yudel Johnson lost to Thailand's Manus Boonjumnong.
Kindelan also excelled, ending the run of Briton Amir Khan.
But team-mate Aragon had less joy in his Olympic comeback, being well outpointed by Kazakhstan's Artayev.
Artayev, who had defeated Russia's double Olympic gold medallist Oleg Saitov in the semi-finals, won a 36-26 decision after a fierce contest.