By Papal Decree 12 June 1923, the Eastern Transvaal (Mpumalanga) was separated from the Transvaal Vicariate and entrusted to Missionaries, Sons of the Sacred Heart (MSFC). In 1979 the MFSC rejoined the Verona Fathers (FSCJ) and are now known as the Comboni Missionaries of the Heart of Jesus (MCCJ).
The Lydenburg Prefecture was raised to the status of a Vicariate on 9 December 1948. Following the establishment of the hierarchy in South Africa, the Vicariate was raised to the status of a diocese on 11 January 1951.
On the 23 June 1958, a number of magisterial districts on the southern boundary of the diocese were excised and incorporated in the Volksrust Prefecture. On the 13 September 1964 the name of the diocese changed to Lydenburg‑Witbank by papal decree and on the 10 November 1988 to Witbank.
The diocese comprises the magisterial districts of Barberton, Belfast, Carolina, Kamhlushwa, Lydenburg, Mapulaneng, Mhala, Middelburg, Nebo, Nelspruit, Nsikazi, Pilgrim’s Rest, Sekhukhune, Waterval‑Boven, White River, Witbank, and portions of Eerstehoek and Groblersdal. Some of these districts are located in the province of Mpumlanga, others in that of Limpopo.