The pair, both aged in their 50s, were arrested and held in Dundrum Garda station.
Gardai said the seizure forms part of Operation Tara, the enhanced national anti-drugs strategy, which was launched by Garda Commissioner Drew Harris in July 2021.
“As part of Operation Tara, gardaí attached to the DMR East Divisional Drug Unit have seized over €1 million worth of heroin and cocaine, following a search operation in Dublin 18 yesterday,” gardai said on Thursday.
“Shortly before 7.30pm yesterday evening, gardaí conducted a search of a residential property in Sandyford. During the course of the search €560,000 worth of heroin and €490,000 worth of cocaine was seized.