An announcement relating to new international opportunities for the dumped teams will be made in due course.
An announcement relating to new international opportunities for the dumped teams will be made in due course, South African Rugby said in a statement.
Pro12 currently consists of four Irish and Welsh teams and two from Italy and Scotland and there has been media speculation that the two relegated South African sides would join them.
The axings were expected as the Cheetahs and Kings had the lowest average attendances and poorest overall playing records among the six Super Rugby teams from South Africa.
Cheetahs are based in central city Bloemfontein and the Kings in eastern coastal city Port Elizabeth.
The other "casualties" will be an Australian team -- either the Melbourne Rebels or the Perth-based Western Force.
Rising costs, exhaustive travel across 15 time zones, dwindling crowds and TV audiences, and a hard-to-understand format are among the reasons for cutting the number of franchises.
Coastal Sharks, Golden Lions, Northern Bulls and Western Stormers will represent South Africa in Super Rugby next season when the competition shrinks from 18 teams to 15.
A slimmer Super Rugby championship will comprise five teams from New Zealand, four from Australia and South Africa, and one from Argentina and Japan.
New Zealand have dominated the competition since its mid-1990s inception, winning 14 finals. Australia have been successful four times and South Africa three times.
"I want to thank the Cheetahs and Kings for the mature and professional manner in which they managed the difficult situation," SA Rugby chief executive Jurie Roux said.
"They took decisions that will not only benefit them, but also South African rugby in general."
Kings host Cheetahs on July 14 in Port Elizabeth in what will be the last Super Rugby fixture for both teams.
Andre Rademan, president of the Eastern Province Rugby where the Kings are based, was upbeat despite the loss of Super Rugby status.
"It has been a roller coaster ride for the franchise for a number of seasons," he told reporters after the cull announcement.
"But there is now a clear and viable way forward for rugby in the Eastern Cape to build on the foundations that have been laid -- particularly in the past season."
"We have enjoyed Super Rugby, but the chance to test ourselves against different opposition in different conditions is a mouth-watering one."
"Therefore, we are not opposed to joining new competitions. With all stakeholders pulling in the same direction we can bring success and excitement to rugby in the Eastern Cape," he said.