There is still a considerable debate about whether socioeconomic or cultural factors underpin the high prevalence of sexual partner concurrency in parts of Southern and Eastern Africa. We analyzed the patterning and correlates of concurrency in a population-based sample of 1182 sexually active 14-24 year olds in Carletonville, South Africa. Potential demographic, socioeconomic and attitudinal risk factors were assessed via a questionnaire. The association between risk factors and respondent reported concurrency were assessed using multivariate logistic regression. Separate models were run for men and women. Point-concurrency rates at the time of the survey and 6 months prior to the survey were similarly high - 19.3 (95% confidence interval, CI 14.2-18.5%) and 16.2% (CI 14.1-18.4%), respectively. Multivariate logistic regression revealed that for men and women, concurrency was not associated with socioeconomic deprivation but was associated with a number of sexual partners, being married and having a partner who was thought to have an additional partner. Female concurrents were more likely to use alcohol, have an older partner and have difficulties negotiating condom usage and refusing sex with their partners. Male concurrents were less likely to use a condom regularly and less likely to wear a condom when their partner asked them to. The strong relationship between respondent and partner concurrency appears to depend on contemporary concurrency, as opposed to the behavior of previous partners. If high concurrency rates are in part driven by positive feedback loops of partner and respondent concurrency, then norm change involving the rejection of concurrents could be self-amplifying leading to a rapid decline of concurrency.