The South African Congress of Trade Unions was established in 1955 after the right wing unions walked out of the South African Trades and Labour Council in 1954 to form the exclusive White, Coloured, and Indian workers’ Trade Union Council of South Africa.
It combined the unregistered African unions affiliated to the Council of Non-European Trade Unions with the 14 registered unions which refused to join the TUCSA. The South African Railways and Harbours Union and the Food and Canning Workers' Union were among the founder members.
The Industrial Conciliation Act, 1956 banned the registration of multi-racial trade unions.
It was explicitly political and was one of the founders of the Congress Alliance in 1955. Its first conference in 1956 proclaimed that the fights for economic and political rights were one and the same. It explicitly campaigned against the Native Labour (Settlement of Disputes) Act, 1953 and urged members to have nothing to do with the Native Labour Officials established by it. SACTU organised factory "cells" which studied Marxist ideology as well as organising techniques.
The organisation shared a building in Plein Street, Cape Town with the Food and Canning Workers' Union and other unions. A Transport National Organising Committee was established in May 1958
SACTU organised a campaign for a national minimum wage of £1 (R2) a day in 1957 with the South African Railways and Harbours Union as a central focus.
In 1961 46 unions were affiliated, of which 36 were African. Their total membership was around 53,000 of which 39,000 were black and they had 63 paid organisers.
In December 1962 the organisation was one of 36 organisations listed in a government proclamation under which 432 people were banned from holding office in any of those organisations, including 45 officials of SACTU and its affiliates.
It produced a journal, called Workers` Unity.
The organisation continued to operate clandestinely. It got some financial support from the International Transport Workers' Federation. From 1973 there was a revival of industrial militancy. The government retaliated with violence and several hundred strikers were shot. But the Bantu Labour Relations Regulations Amendment Act in 1973 did permit some industrial activity within a restrictive framework of works committees. By 1976 there were about 40,000 African union members.