Steven Kelly, 19, a soldier, and Lee Dunnachie, 22, who recently became a father, died after taking the powerful drugs.
The two men died several miles apart in Ayrshire and did not know each other but police believe they were victims of the same batch of pills.
Results from post-mortems on both men are expected today but it is believed the drugs they had taken were around six times stronger than the normal ecstasy tablet.
Strathclyde Police said no arrests had been made and appealed for witnesses to come forward to help identify the source of the Class A drugs.
It is understood Mr Dunnachie had earlier been to a party in a flat which was attended by around 100 people.
Paramedics were called to Colonsay House in Prestwick’s Pleasantfield Road at around 9.40am on Saturday.
Mr Dunnachie was taken to Ayr Hospital but it is not known whether he was already dead.
Hours earlier, Mr Kelly was found dead at his house in the village of Patna.
He is reported to have become a father less than a month ago.
Mr Dunnachie is said to have posted on Facebook that he could not sit still and was struggling to go to the toilet.
Tributes were left on the social networking website after his death was confirmed.
Kayleigh Dunnachie wrote on her Facebook wall: “Just another angel up there. Keep the gates open for me and leave the stair way clear … Sleep tight xxxxx ur in my heart forever an always xxxxxx”.
Siobhan Sutherland wrote: “Am in shock was a brill pal he just phoned me the otha day .”
Police officers have made contact with health and social workers, as well as alcohol and drug action teams.
Det Insp Craig McArthur of Strathclyde Police, who is leading the investigation, said: “Our enquiries have revealed that the pills are extra strong.
“If that is the case then somebody could be popping a tablet and it could have the effect of taking six tablets.
“It is a lot, lot stronger.”
The deaths come 17 years after three men died after taking ecstasy at a notorious Ayr nightclub that was later closed.
Andrew Dick, 19, from Glasgow and John Nisbet, 18, of New Cumnock, Ayrshire, died in April 1994 after going to the Hanger 13 club.
Andrew Stoddart, 20, of Rigside, Lanarkshire, died in August 1994 after taking the drug in the same club.
No-one was prosecuted over the deaths but McCalls Entertainment lost its licence and Hanger 13 was closed in 1995.
In 1993, Lenzie student Laura Hay, 19, died five days after taking the drug at a rave in the SECC in Glasgow.
In May 2001, two teenage women students died after taking so-called super-strength ecstasy pills.
Pictures of the bloated body of Lorna Spinks, 19, shocked the nation.
Britain’s most high-profile ecstacy victim was Leah Betts, 18, from Essex.
Her parents released a photograph of her as she lay in a coma before dying in 1995, to warn others about the drug’s dangers.
The only way to know the chemical make-up of ecstasy is to use a testing kit. The resulting colour change shows what the pill contains.
The kits are legal to possess, but their use obviously involves possession or supply which carries severe penalties.
In Holland, the Government subsidises pill tests in an attempt to protect users against contaminated tablets..