The death of a 73-year-old Vietnamese from bird flu, has taken the country's death toll from the epidemic to 39.
Nineteen of those deaths have been since the virus returned in December.
The Hanoi resident was admitted to hospital on June 23 and was one of four people infected by the H5N1 virus being treated in hospital.
Hospital officials say the patient died on Tuesday, but gave no further details.
Doctors at the hospital could not be reached immediately for comment.
According to the Health Ministry bird flu has infected 60 people since it returned to Vietnam in December.
The World Health Organisation (WHO) has again repeated its warning that the H5N1 virus could mutate into a form which could pass easily between people and cause a global pandemic.
WHO has advised Vietnam and the rest of the world to remain vigilant in its influenza control efforts because influenza viruses are inclined to change frequently.
Hans Troedsson, WHO representative in Vietnam, says that the risk of a pandemic remains, but with further research and international collaboration, the possibility of lessening its impact is a goal that may ultimately be realised.
To date the virus, which arrived in Asia in late 2003, has also killed twelve Thais and four Cambodians.
A campaign by the Health Ministry will attempt to raise public awareness and clean up the environment between now and December to combat the poultry virus.
The virus appears to thrive best in the winter but still jumps to humans in the hot months.
The Ministry says there is a high risk that outbreaks could turn into a large-scale epidemic in the winter.
The Agriculture Ministry says that on a trial basis, chickens would be vaccinated in two provinces from Aug. 1, after the vaccine for poultry had been tested successfully.