Introduction: Burden of HIV and AIDS is considerably different among regions and countries of the world. The aim of this study was to assess of inequality in the prevalence of HIV, according to human development index among countries of the world. Methods: In this study the desired outcome was prevalence of HIV, which estimated in 100 countries in 2012. The annual report of UNAIDS was used for prevalence of HIV in countries. Also, we used data for the human development index of the countries from UNDP. We defined inequality of human development index in the prevalence of HIV by using the concentration index. Results: Concentration index for prevalence of HIV among 25-49 years adults was -0.217574 (95 CI: -0.07422, -0.361125). This index indicated the inequality in the prevalence of HIV base on the human development index and concentrating more HIV subjects in poor countries. Also concentration indexes in the prevalence of HIV among young males and females were 0.229920 and -0.200014 respectively. Conclusion: Results of this study emphasized on inequality in the prevalence of HIV and concentration HIV in countries with lower human development index, so the international organization must perform fundamental actions to help these countries, such as prevention, care and treatment programs