Gauteng, South Africa's economic powerhouse, has long been dependent on immigration to supply its labour requirements, a phenomenon deeply rooted in the province's early economic history and the development of mining and heavy industry. Although migration has contributed to the development of the province, it also poses challenges to the provincial government partly through the added burden on state-financed services and programmes. In this context, this study aims to quantify and describe migration to and migrant labour in Gauteng by using the 2001 Census and the September 2002 Labour Force Survey. South African immigrants to the province (or in-migrants) were defined in one of two ways: individuals who were born in South Africa, but outside of Gauteng, or individuals whose most recent move in the 1996-2001 period was to Gauteng from one of the other eight provinces. In-migrants are described in terms of their demographics and educational and employment status. Further, in-migrants' access to public services including electricity and water and other indicators of their living standards, such as housing, were analysed. As far as possible, the analysis compared in-migrants to non-migrants and intra-Gauteng migrants in order to provide insight into special benefits or challenges that in-migrant households may present. The Labour Force Survey module on migrant labour allowed the profiling of migrant labourers and the approximation of economic links between Gauteng and other provinces as represented by remittances. The study found that a large proportion of Gauteng residents were born outside the province, or moved into the province in the inter-census period, indicating a relatively mobile population. Although in-migrants constitute approximately half of the population with post-matric qualifications, they are overall less educated than the rest of the Gauteng population and are more often engaged in relatively lower skilled occupations and sectors. It is concluded that significant levels of in-migration are likely to continue for at least the medium-term, with in-migrants posing important challenges specifically in the areas of health, housing and infrastructure provision. Through remittances, the economic situation of the province and of migrant workers may also have important consequences in the rural areas of the provinces of Limpopo, Eastern Cape, KwaZulu-Natal and Mpumalanga.