Margaret Chuene Mncadi was born in the Eastern Transvaal, she graduated from Fort Hare and the medical school of the University of the Witwatersrand. She established a medical practice in Benoni, where she became active in the local African National Congress (ANC). In 1956 she moved to Natal and took over the Ixopo practice of Winston Conco, then a defendant in the Treason Trial. In 1959 she led protests against the extension of passes to women and was elected vice-president of the ANC Women's League in Natal. Since 1960 she has practiced medicine in Swaziland.
