OBJECTIVES: This study aimed to assess the cross cultural validity and reliability of Health Utility Index (HUI3) in UK HIV population. METHODS: The study was approved by local research ethics committee. All adult patients receiving HIV care in Cardiff were approached in the outpatient clinic and recruited into the study after giving written informed consent. Participants were required to complete the HUI3. Variables analyzed include QOL score, CD4+ category, HIV stage, antiretroviral (ARV) usage and viral load using Spearman's rank test, Kruskal-Wallis and Mann-Whitney U test. RESULTS: In total, 103 (98%) of participants completed the questionnaire. The average age of the participant was 40.8 years (±10.7 SD) and 81 were male. HUI3's was found to be reliable in most attributes (Cronbach's alpha 0.68), except in vision, hearing and ambulation. Four attributes (ambulation, emotion, cognition and pain) correlated significantly with QOL score (p<0.002) after controlling for antiretroviral use, clinical, and CD4+ categories. Findings also revealed no significant difference and correlation between QOL score and CD4+ count, viral load count and HIV clinical categories. There appears to be a stronger correlation (r=-0.19) and mean difference (P=0.08) between QOL score and antiretroviral use but this did not reach statistical significance. An interesting pattern was observed whereby asymptomatic patients and those not using antiretroviral (ARV) therapy had a lower QOL score than AIDS patients. Class of ARV also appeared to affect QOL score but was not significant statistically (P=0.2). CONCLUSION: The findings of this study support validity and reliability of HUI3 in UK HIV population and therefore could be used with confidence in comparative study of HIV treatment. The results also suggest benefit of ARV use in improving patient QOL and also the different effect of ARV regimen had on the score; however this requires further investigation in a controlled study.