OBJECTIVE: Triple antirhetroviral therapy (ARV) has been demonstrated to be cost-effective and is widely accepted as standard treatment for HIV/AIDS. Because of the substantial costs of ARV and the high prevalence of HIV in Thailand, it was necessary to compare the treatment costs of patients receiving and not receiving ARV before the Thai government would include ARV for their Universal Health Coverage Program. METHODS: Retrospective data from medical charts of AIDS patients receiving and not receiving ARV were reviewed during July - November 2002. For the ARV group, only the patients treated with triple ARV more than one year were included. One-year treatment costs including medication, laboratory, and hospital admission and out patient department (OPD) costs were analyzed and compared. RESULTS: The average annual treatment cost for the 93 patients in the ARV group was Baht 87,168 ($US 2,075), which was 7.9 times greater than the average cost of the 91 patients in the non-ARV group (US$ 264). The average ARV drug cost per day was Baht 223.5 (US$ 5.3). ARV drug costs contributed 93.6% to the overall treatment of the ARV group. For the non-ARV group, the major cost was hospital admission and OPD costs, which were 97.5 % of treatment costs. Although hospital admission and OPD costs of the ARV group was only 6.4% of those in the non-ARV group, saving these costs in ARV group could not compensate the ARV drug cost. CONCLUSIONS: Cost of ARV drug did not out weight cost saving from hospital admissions and OPD costs. Only a decrease in ARV costs could improve patients’ access to ARV. A one dollar per day triple ARV, GPO-VIR ®, produced by the Thai government might lead to government subsidization of ARV for all AIDS patients in Thailand.