The man known as 'Blade Runner' missed out on a spot in the individual 400m event after failing to achieve the qualifying time by a quarter of a second earlier this season, but South African Olympic chiefs SASCOC have relaxed their rules and will allow him to run for both South Africa's 4x400m team and the individual 400m event.
It will be the second appearance at a major championship for the 25-year-old, who made the World Championship semi-finals and picked up a silver medal with the South African 4x400m quartet in Daegu last year.
"Today is really one of the happiest days of my life!" Pistorius wrote on Twitter after learning of his selection.
"Thank you to everyone that has made me the athlete I am! God, family and friends, my competitors and supporters! You have all had a hand!"
Pistorius did beat the Olympic qualifying standard of 45.30 seconds in a meeting in Pretoria last March, but had failed to reproduce that form in an international meeting - one of the requirements for individual selection for South Africa - with his season's best at a qualifying race being 45.52.
Yet the runner nicknamed 'the fastest man on no legs' will be permitted to run in the individual 400m race as well as being included alongside Willem de Beer, Ofentse Mogawane and Shaun de Jager for the relay.
South African Olympic chief Gideon Sam congratulated the double amputee, who has run against able-bodied fields on carbon fibre blades since being cleared to do so by the Court of Arbitration for Sport in 2008.
"As I have said many times before, we are not taking passengers to London," he said. "Everyone has met selection criteria and are genuine Olympic Games material. I wish them all the best."