Purpose: To investigate the effect of androgen deprivation therapy (ADT) on health-related quality of life (HRQOL) in Asian men with all stages of prostate cancer. Materials and Methods: READT (real-life evaluation of the effect of ADT in prostate cancer patients in Asia) was a multi-center, prospective observational study involving six sites across four Asian populations. We enrolled eligible prostate cancer patients, who opted for ADT alone or in combination without prior neoadjuvant or adjuvant ADT within 12 months. The EuroQoL-5 dimensions, 5 level scale (EQ-5D-5L) utility index scores and visual analog scale (VAS) were evaluated at baseline, month 6 and month 12. Results: A total of 504 patients were recruited into READT between September 2016 and May 2020 with 52.9% diagnosed with metastatic prostate cancer. The EQ-5D-5L was evaluable in 442/504 (87.7%) of patients. Overall baseline EQ-5D-5L utility index score was 0.924 (interquartile range [IQR] 0.876–1.000). We observed a statistically significant difference in baseline EQ-5D-5L utility index score among different populations with a median EQ-5D-5L utility index score of 1 for Taiwan & Hong Kong, 0.897 for China and 0.838 for Malaysia. Similar trend was observed throughout multiple treatment time-points. Stage IV prostate cancer were significantly associated with a lower baseline EQ-5D-5L utility index score compared to stage I–III prostate cancer, producing a median disutility value of -0.080. Participants had a high median VAS (80, IQR 70–90), indicating good overall health on average during ADT initiation. Conclusions The study highlights the differences in health state utility index scores among various Asian prostate cancer patients receiving ADT at real-world setting. Our findings will be informative and useful in cost-effectiveness evaluation and policy decision making.