This study examined HIV vaccine acceptability among immigrant Thai residents in Los Angeles, California. We combined a qualitative research method (focus groups) with an innovative market research method (conjoint analysis). Focus groups explored social issues, concerns, barriers and motivators associated with HIV vaccine acceptability. Conjoint analysis was used to assess preferences among eight hypothetical HIV vaccines with varying attribute profiles and the impact of various attributes on acceptability. Five main themes were identified in the focus groups regarding acceptance and utilization of preventive HIV vaccines: (1) vaccine characteristics, such as efficacy, physical side-effects and cost, (2) fear of a vaccine, (3) vaccine acceptability and optimism, (4) social and family responses and (5) behavioral disinhibition. Conjoint analysis revealed HIV vaccine acceptability ranging from 7.4 (SD = 19.4) to 85.2 (SD = 24.3) across eight hypothetical vaccines. The vaccine with the highest acceptability had the following attributes: 99% efficacy, no side-effects, 10 years of protection, protects against one sub-type, free, one dose and given by injection. Vaccine efficacy had the greatest impact on acceptability (51.4, p=.005), followed by side-effects (11.1, p=.005) and duration of protection (8.3, p=.005). Despite some apprehensions and concerns, Thai residents perceived an HIV vaccine as making an important contribution to society and to protecting oneself and one's family from HIV infection. Nevertheless, acceptability of a partially efficacious vaccine may be low, suggesting the need for tailored social marketing interventions that might emphasize a collectivistic rather than an individualistic focus. Assessing HIV vaccine acceptability using a mixed-method approach is feasible with Thai residents and should lend itself to HIV vaccine research with other Asian Pacific Islander populations in the US. © 2008 Taylor & Francis.