Objective: To examine behavioral history, beliefs, and vaccine characteristics as predictors of HIV vaccine acceptability. Methods: Two hundred forty-five US under graduates were surveyed regarding their sexual history, risk beliefs, and likelihood of accepting hypothetical HIV vaccines. Results: Multivariate regression analysis indicated that vaccine acceptability was predicted by lifetime sexual partners, high perceived HIV susceptibility, low danger invulnerability, and high psychological invulnerability. Low perceived risk was associated with basing decisions on vaccine cost. Conclusions: HIV vaccine acceptability was predicted by behavioral risk and perceived HIV susceptibility, but also by general feelings of invulnerability to physical and psychological harm.