Zidovudine (AZT) plus single dose nevirapine (AZT+sd-NVP) were provided to pregnant women with HIV infection who have CD4 > 200 cell/mm3 for preventing vertical transmission. However, three-drug regimen is provided to pregnant women with HIV infection regardless CD4 cell count in high resource countries. Mother to child transmission rate in pregnant women in the receiving three-drug regimen was lower than that in pregnant women receving AZT+sd-NVP. On the other hand three-drug regimen is expensive so it could be a finance handle in limited resource countries. The implement of the change is still to be determine. The objectives of this study are to evaluate the cost-effectiveness of three-drug antiretroviral compared to AZT+sd-NVP and assess the feasibility of implementation of the use of three-drug antiretroviral regimen as the standard regimen for the prevention of mother-tochild transmission of HIV. The study shows that three-drug regimen is more cost-saving because it saves cost of treatment in newborn with HIV infection. The implementation of the three-drug regimen is feasible in the health care system in Thailand. Moreover, the adherence of three-drug regimen is good in pregnant women.