Purpose: As the incidence of prostate cancer rises in Asian countries, notable disparities in life expectancy, economic status, and education levels are observed. This study aimed to use the Human Development Index (HDI), which reflects these factors, to explore differences in prostate cancer diagnosis, staging, and initial treatment across various Asian nations and areas, and uncover the impact of socioeconomic factors on patient outcomes. Methods: We analyzed patients diagnosed with prostate cancer between January 2016 and December 2018 who were enrolled in the Asian Prostate Cancer Study Group (A-CaP). Patients were grouped into three HDI categories (medium, high, very high). A statistical comparison was conducted to evaluate differences in diagnostic methods and initial treatments across 12 Asian countries and areas based on HDI classification. Results: In total, 35,776 prostate cancer patients were included. Patients in the very high HDI group had lower PSA levels, fewer ISUP Grade 5 cases, and reduced metastatic disease (M1) compared to the other groups. Advanced diagnostic modalities (e.g., CT, MRI, and bone scintigraphy) were more commonly used in the very high HDI group. Imaging modalities were less frequently used in medium HDI countries with low PSA, and in high HDI countries with high PSA. Regarding treatment, patients in very high HDI countries and areas were more likely to receive radiation therapy or active surveillance. Surgical treatment was more common for metastatic patients in high and medium HDI countries and areas. Conclusion: This study highlights significant differences in prostate cancer management across 12 Asian countries and areas, emphasizing the influence of HDI on diagnostic and treatment outcomes.