Levels of HIV infection are particularly high amongst migrant workers in sub-Saharan Africa. This paper presents a case study of one such vulnerable group of migrants-underground workers on the South African gold mines-and highlights the psychosocial context of HIV transmission in the mining setting. On the assumption that social identities serve as an important influence on peoples' sexual behaviour, the study examines the way in which miners construct their social identities within the parameters of their particular living and working conditions. It also identifies some of the key narratives used by miners to make sense of their experience in the realms of health, ill-health, HIV and sexuality. Masculinity emerged as a leading narrative in informants' accounts of their working life, health and sexuality, and the paper examines the way in which the construction of masculine identities renders miners particularly vulnerable to HIV. The implications of these findings for HIV educational interventions are discussed.