The car in which the men were travelling collided with a people carrier at around 10am.
The collision took place on the N72 Dungarvan-Lismore road between the junctions with the N25 and the R672, north of Dungarvan.
The six occupants of the people carrier — understood to be two adults and four children — were airlifted to Cork University Hospital and University Hospital Waterford. At least two of these are understood to be in critical condition.
The bodies of the men who died were removed to University Hospital Waterford for postmortem examinations.
A full examination of the car in which the deceased were travelling was delayed due to the extent of the damage, gardaí confirmed.
The road was closed overnight, with diversions put in place.
Gardaí have appealed for witnesses, who may have travelled this stretch of road and can assist with their investigation, to contact Dungarvan Garda Station (058-48600) or any Garda station.
The collision was one of a number of serious road traffic accidents that occurred over the weekend.
Gardaí in Dublin are appealing for witnesses after a woman in her 70s was hit by a car as she crossed a road on the city’s southside.
The collision occurred at approximately 7.15am yesterday on Sundrive Rd, beside Sundrive Park.
The woman was taken to St James’s Hospital with injuries described as serious, while the driver of the car was uninjured.
A section of the road was temporarily closed to allow for a technical examination by gardaí.
Meanwhile, in Cork, a 29-year-old woman was killed after her car, in which she was the sole occupant, left the N20 Cork-to-Limerick road at around 10.25pm on Friday night.
The woman, named locally as Mandy O’Leary, from Farranree in Cork city, was driving northbound when the incident took place, near the turn off for Blarney.
She was treated at the scene for her injuries, but was pronounced dead and her body was removed to Cork University Hospital for a post-mortem examination.
Ms O’Leary’s removal will take place this evening at Coughlan’s Funeral Home, Shandon Street, ahead of funeral Mass tomorrow at the Church of the Resurrection, Farranree.