The clashes followed a match between the al-Ahly and al-Masry clubs in February of that year, and left 74 football fans dead.
The riots - Egypt's worst-ever football disaster - began after a top-league game at the stadium.
The case, and earlier sentencing, fuelled tensions and bouts of violence.
The verdict came as part of a retrial of 73 defendants in the case, in which another 40 defendants were sentenced to up to 15 years in prison.
Other defendants were acquitted. The verdicts can be appealed against.
•74 people killed in Port Said stadium on 2 February 2012
•Clashes broke out between rival fans of clubs al-Masry and al-Ahly
•Fans flooded on to pitch attacking al-Ahly players and fans as match ended
•Most died of concussion, cuts and suffocation
Several police officers were tried in the case, alongside officials from al-Masry as well as Port Said fans.
None were among those who received death sentences, but Port Said's former security chief was sentenced to five years in prison.
Police were accused of letting fans from the local team al-Masry attack supporters of Cairo club al-Ahly, who had been vocal in supporting the overthrow of President Hosni Mubarak.
Many of the dead were crushed when panicked fans tried to escape from the  stadium after a post-match pitch invasion by al-Masry supporters.
The violence sparked unrest in the capital, Cairo, where another 16 people died.
During the clashes, then-President Mohammed Morsi declared a state of emergency in the city.
An Egyptian court has upheld death sentences for 11 men over their involvement in deadly football stadium violence in 2012 in Port Said.