Among the victims who were dead is one police officer, Vasip Sahin, The report adding that it was a terror attack in the City.
Not only 35 were dead but at least another 40 were injured in the attack which took place in a popular Reina nightclub, in the Ortakoy part of the city, at about 01:30 local time (23:30 GMT).
The governor pointed out that one attacker was involved, and the CNN Turk also reported that the Killer was dressed in a Santa Claus costume.
According to reports there were several hundred people in the nightclub at the time, some of whom are believed to have jumped into the Bosphorus to escape.
The city had been on high alert for any terror attacks, with as many as 17,000 police officers on duty in the city.
This attack in Instabul is the latest in a string of attacks in Turkey over recent months, which many are carried out by so-called Islamic State (IS) or Kurdish rebels.
On another occassion, a Russian ambassador Andrei Karlov was shot dead by off-duty Turkish policeman Mevlut Mert Altintas as he gave a speech in the capital Ankara in December.
After the Firing, the killer was heard shoutin the murder was in revenge for Russian involvement in the conflict in the Syrian city of Aleppo.