OBJECTIVE: To determine whether the reduction of opportunistic infection treatment cost among HIV patients offsets their increased cost after providing the triple ARV combination drug, GPO-VIR® , which costs only US $ 1 (40 baht) per day. METHODS: Only the HIV patients who had CD4 cell count less than 200 cell/mm3 at the initiation of receiving GPO-VIR were recruited in the study. Clinical and cost data of the HIV patients, one year before and at least 6 months after receiving GPO-VIR, were collected. Cost-consequences analysis was employed based upon provider perspective. RESULTS: Of the 78 HIV patients, 52.6% were females and 80.8% had the CD4 cell count level less than 100 cell/mm3 at the initial treatment. The mean of the CD4 cell count level (179.2 ± 94.00) after receiving GPO-VIR significantly increased from baseline (56.5 ± 52.9) at the initial treatment (P=0.000). The incidence rate of specific OI at OPD visit substantially decreased including Pneumocystis Carinii Pneumonia (PCP), Cytomegolovirus (CMV), Tuberculosis (TB), and Cryptococcal Meningitis. Four HIV patients (5.1%) were admitted with severe ADR including two cases of acidosis, one case of renal failure, and one case of hepatic failure. The treatment costs before receiving GPO-VIR were 108.7 US $ per patient per year (PPPY). After receiving GPO-VIR, the total costs were 567.1 $ PPPY including 459.2 $ PPPY for the GPO-VIR cost. The hospitalization cost reduced from 49.5 $ PPPY to 20.4 $ PPPY after receiving GPO-VIR. Cost of ADR treatment was 48.4% of overall hospitalization cost. CONCLUSIONS: After receiving GPO-VIR, although the overall cost did not outweigh the cost prior to the ARV treatment, it substantially decreased severe OI and hospitalization cost. The positive impact of GPO-VIR enhances provider to increase universal coverage of GPO-VIR for all eligible HIV patients in Thailand.