In sub-Saharan Africa, risk of HIV infection was associated with increased education, mobility and income in studies completed before 1996. Some later studies found no association or a negative socioeconomic gradient in prevalent HIV infection. The social epidemiology of HIV infection among South African young people remains poorly understood. This study examined the association between socioeconomic factors and HIV risk among unmarried young people aged 14-25 years in rural South Africa in 2001. Some 916 males (73.6% of those eligible) and 1003 females (80.8%) were included in the study sample. Households were ranked into those that were "very poor", "poor, but a bit better off" or "doing OK". Most young people attended school, though this was associated with increased wealth among the females. Those not attending school were mostly unemployed. Temporary migration was increasingly common with greater age but was not associated with household wealth. Low HIV awareness and risky sexual behaviour characteristics were widespread. HIV prevalence was 5.6% among males and 12.2% among females. Household wealth was not associated with HIV risk except that young women from wealthier households more often reported condom use. Those attending school of both sexes reported lower numbers of sexual partners than those not attending. Young women attending school reported partnerships with lower frequency of intercourse, men closer in age to themselves and higher levels of condom use. HIV prevalence was lowest among young men attending school. Temporary migrants of both sexes reported greater levels of HIV awareness than those staying at home, while female migrants also reported more condom use. In this study, young people were at high risk of HIV infection, particularly those not attending school. Young people remaining in rural areas were also at high risk of new infection. Programmes that reach these young people and increase educational opportunities might help reduce HIV infection rates.