Men having sex with men (MSM) now account for 7% of all HIV/AIDS cases in China and there is growing awareness that internal rural-to-urban migration might shift the HIV epidemic within China by broadening social and sexual mixing. About 70% of HIV/AIDS infections are among rural residents, of whom 80% are males and 60% aged 16-29. This young, male, rural-to-urban migrant population has been identified as the 'tipping point' for the AIDS epidemic in China. A subgroup of these migrants is the 'money boy' population, i.e. those who engage in same-sex transactional sex for economic survival. However, the literature addressing money boys is very limited. The present study aims to elucidate factors for preventing substance abuse and HIV among two types of money boys 'gay-identified' and 'non-gay-identified' living in the Shanghai metropolitan area. This work is conceptually underpinned by Chng et al.'s (2003) tripartite model, which postulates that risk behaviors (e.g. substance abuse) engaged in by transient or non-native individuals are often shaped and regulated by factors in the home environment, migration experience and current environment. Results reveal gay and non-gay money boys were not significantly different in age, income, marriage status and education. Both groups shared similar patterns of substance use. Both groups had high self-reported depressive symptoms and low HIV knowledge. However, sexual orientation differentially predicted HIV testing, with gay money boys more likely to be tested for HIV. Non-gay money boys showed fewer sexual risks. HIV prevention targeting MSM (including money boys) within rapidly changing China is discussed, as are methodologies and outreach strategies most effective for particular subgroups of MSM.