The 56-year-old Qatari victim, who already had chronic illnesses, died on August 31, a week after she was admitted to intensive care at a Doha hospital, newspapers quoted the emirate's Supreme Council of Health as saying.
Two other cases of infection have been registered in the Gulf state, including two men, aged 59 and 29, who were hospitalised last month.
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.
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 former's 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.