The Western Cape High Court has set aside all nuclear deals with South Africa.
The court ruled on Wednesday all the deals were unlawful and unconstitutional. This includes deals with the United States, Russia and South Korea.
Earthlife South Africa and the South African Faith Communities' Environment Institute applied to the courts in October to challenge government's decision to buy 6,9GW of nuclear power without a debate in Parliament.
The NGOs also argued that the energy department acted unlawfully when it moved the procurement of the nuclear energy to Eskom. That was also ruled unconstitutional due to the lack of public consultation.
Lawyer for government Marius Oosthuizen had argued that deals between countries do not need to be debated in Parliament as it was an international agreement. Oosthuizen also said the deal was not the equivalent of a commercial agreement.