Turkey’s Interior Minister Suleyman Soylu said the figure included 30 police officers, seven civilians and one more person whose identity had yet to be determined.
The minister also put the number of wounded at 155 and said 13 suspects had been detained in connection with the attack on Saturday night.
The attack was the latest large-scale assault to traumatise a nation confronting an array of security threats.
The civilian death toll was lower because fans had already left the newly-built Vodafone Arena Stadium after the match when the blasts occurred. Witnesses also heard gunfire after the explosions.
President Recep Tayyip Erdogan said in a statement: “We have once again witnessed in Istanbul the ugly face of terror which tramples on every value and decency.”
The first bomb went off just outside the facility known popularly as Besiktas Stadium after the local team and neighbourhood. The second blast that came moments later was attributed by authorities to a suicide bomber.
Police cordoned off the area as smoke rose from behind the stadium and ambulances began ferrying the wounded to hospital. Glass from the blown-out windows of nearby buildings littered the pavement.
There was no immediate claim of responsibility. This year, Istanbul has witnessed a spate of attacks attributed by authorities to Islamic State or claimed by Kurdish militants. A state of emergency is in force following a failed July 15 coup attempt.
Mr Soylu acknowledged the country was struggling against “many elements” trying to compromise its fight against terrorism.
Turkey is a partner in the US-led coalition against IS and its armed forces are active in neighbouring Syria and Iraq. It is also facing a renewed conflict with an outlawed Kurdish movement in the south east.
The first and larger explosion took place after Besiktas beat visitors Bursaspor 2-1 in the Turkish Super League.
Mr Erdogan said the timing of the attack aimed to maximise the loss of life and vowed the nation would overcome terrorism.
Mr Soylu said the first explosion was caused by a passing vehicle that detonated in an area where police special forces were located at the stadium exit right after the match. A riot police bus appears to have been the target.
Kurdish militants often target security forces while ‘IS’-linked attacks have targeted tourists and the broader public.
Deputy prime minister Numan Kurtulmus said a person who had been stopped in nearby Macka Park committed suicide by triggering explosives.
Mr Kurtulmus told the private news channel CNN Turk that “arrows point to the PKK”. He was referring to the outlawed Kurdistan Workers’ Party, which has waged a decades-long insurgency.
Investigators, including Istanbul police chief Mustafa Caliskan, were quickly on the scene. Forensic experts in white uniforms scoured the vicinity of the stadium and the vast park where the suicide bombing took place.
The Besiktas sports club “strongly condemned” the attack and said an employee of one of its stores was among the fatalities, as well as a member of its congress who was responsible for security at the stadium.
Bursaspor reported that none of the wounded were its fans and issued a statement wishing “a speedy recovery to our wounded citizens”.
A statement from Prime Minister Binali Yildirim’s office declared a national day of mourning and ordered flags to fly at half-mast across the country and at Turkey’s foreign missions.
The Turkish Football Federation condemned the attack and announced that one minute of silence would precede all matches in Turkey’s professional and amateur soccer leagues on Sunday and Monday.
Flags at all stadiums will be at half-mast and there will be no music played during matches.
Turkey’s pro-Kurdish People’s Democratic Party, or HDP, released a statement “strongly condemning” the attacks and saying it “felt great sadness and shared in the sorrow”.