An emerging HIV epidemic can be seen among men who have sex with men (MSM) in Vietnam, with prevalence as high as 18%. Transactional sex represents a risk factor for HIV transmission/acquisition among MSM globally, particularly in urban contexts, but remains largely underinvestigated in Ho Chi Minh City (HCMC), Vietnam. In 2010, 23 MSM who reported exchanging sex for money in the last month completed a brief survey and semistructured qualitative interview at The Life Centre, a non-governmental organization in HCMC, to assess sociodemographics, individual- and structural-level HIV risk factors and explore acceptable future prevention interventions. Participants' mean age was 24 years. Equal proportions of respondents self-identified as heterosexual/straight, homosexual/gay, and bisexual. Participants had a mean of 158 male clients in the past year, with a median of 60 male clients in the past year (interquartile range [IQR]=70) and reported inconsistent condom use and inaccurate perceptions of HIV risk. Nearly half of the sample reported engaging in unprotected anal sex with a male partner in the past 12 months and one-third with a male client. Major themes that emerged for HIV prevention interventions with male sex workers were those that: (1) focused on individual factors (drug and alcohol use, barriers to condom use, knowledge of asymptomatic STIs, enhancement of behavioral risk-reduction skills, and addressing concomitant mental health issues); (2) incorporated interpersonal and relational contexts (led by peer educators, built interpersonal skills, attended to partner type and intimacy dynamics); and (3) considered the exogenous environments in which individual choices/relationships operate (stigma of being MSM in Vietnam, availability of alternative economic opportunities, and varied sexual venues). HIV prevention efforts are needed that address the specific needs of MSM who engage in transactional sex in HCMC. Universally, MSM endorsed HIV prevention interventions, suggesting a need and desire for efforts in this context.