12 January 1980
In May 1962 Dennis Brutus, Secretary of the South African Sports Association, wrote to Otto Mayer, the then Chancellor of the International Olympic Committee (IOC), requesting that the South African National Olympic Committee (SANOC) be expelled from the International Olympic Committee because of the country’s policies of racial discrimination. Subsequently, in 1964, SANOC was banned from taking part in the 18th Olympic Games in Tokyo over its refusal to condemn apartheid. This came after the committee gave SANOC one last chance to make the declaration within 50 days or face the ban. The country was readmitted to the international stage in the early 1990s.
References

O’Malley, P. ‘1980’, from Nelson Mandela Centre of Memory and Dialog, [online], Available at www.nelsonmandela.org.za [Accessed:13 December 2013)|

BBC, ‘1964: South Africa banned from Olympics’, 18 August, [online], Available, at https://news.bbc.co.uk[Accessed: 13 December 2013]