The prevalence of adult HIV/AIDS in Thailand is declining due to intense prevention strategies, but it still continues to be a critical health problem with a prevalence of 1.5%. Several HIV vaccine candidates for the prevention of HIV infection or progress to AIDS were examined in clinical trials. We evaluated the cost-effectiveness of a vaccination regimen (rBCG prime-rDIs boost) currently in its pre-clinical phase. The cost-effectiveness of three interventions (vaccination, highly active antiretroviral treatment [HAART], and the combination of the two) through an existing vaccination program was assessed in a Markov model. The disability preventing HIV infection was assumed to be 30%. The cost of the vaccine was estimated on the basis of its predicted production capacities in Thailand. The incremental cost-effectiveness ratios of vaccination, HAART, and combination were about $US75, $US610, and $US 267 per DALY averted compared with the do-nothing strategy in the base case. The HAART-only strategy seemed to be less cost-effectiveness than the other options under the current assumptions. Sensitively analysis indicated that the new HIV infection rate and the vaccination efficacy could affect the results.