The man died on Friday after he showed symptoms of the coronavirus on August 17, Qatar's Supreme Council of Health said, adding that the man had been suffering from a chronic illness.
Earlier in the week, Qatar said a woman died after being infected, and that two other cases have been registered, including two men, aged 59 and 29, who were hospitalised last month.
On Saturday, the council said that an infected man has been cured.
Another Qatari died of the virus in a hospital in Britain on June 28.
The virus has killed 50 people out of 108 confirmed cases of infections, the World Health Organisation said on its website on August 30. Saudi Arabia is the country worst hit by MERS, with 44 fatalities.
MERS -- Middle East Respiratory Syndrome -- is considered a cousin of the SARS virus that erupted in Asia in 2003 and infected 8,273 people, nine percent of whom died.
Like SARS, it is thought to have jumped from animals to humans, and shares the same flu-like symptoms -- but differs by causing kidney failure.
According to research published last month in the American health journal Emerging Infectious Diseases, MERS was transmitted to humans from bats, but a study in the Lancet found the virus could have come from camels.