Mehmet Ali Kocyigit died on Sunday in a hospital in the east of the country.
Officials had earlier said his death was not caused by bird flu, but changed the diagnosis in an announcement late on Wednesday.
His sister, Fatma, has also been diagnosed as having the disease and remains seriously ill.
The two cases are the first incidents of bird flu in humans to be reported outside of East Asia.
However, the World Health Organisation in Geneva said the
UN body had no official confirmation that the cases in Turkey
involved the H5N1 strain.
The deadly H5N1 strain of bird flu has killed more than 70 people in east Asia since 2003 and forced the slaughter of millions of birds.
Most of the dead have worked or lived on farms and have been in close contact with fowl.
Turkey, which lies on the path of migratory birds that are believed to spread the virus, has suffered two outbreaks of the highly contagious disease among poultry in the past three
Veterinary experts across Europe have been on alert, culling birds and taking other precautionary measures since October outbreaks in Turkey and Romania.
Most of Europe imposed a ban on imports of Turkish live birds at the time, but the measure was subsequently eased.
Experts say a bird flu pandemic among humans could kill millions around the globe and cause massive economic losses.
The virus remains hard for people to catch, but there are fears it could mutate into a form easily transmitted among humans.