Background: In Ethiopia the first case of HIV infection was identified in 1984. Since then HIV/AIDS has created an enormous challenge to several communities, affecting the social and economic well-being of the entire nation. Realizing the enormous consequences of the epidemic, the Ethiopian government deployed tremendous efforts to create HIV awareness in order to bring changes in HIV-related behaviors to reduce the risk of HIV infection. Therefore, it is necessary to assess the role of HIV-related knowledge, attitude and behavior in HIV/AID prevention in Ethiopia. AIM: The aim of the study was to assess the changes in HIV-related knowledge, attitude, and behavior between 2005 and 2011 and its impact on HIV status among Ethiopians. METHODS: The study used a nationally representative sample from the cross sectional years of 2005 and 2011 Ethiopian Demographic and Health Survey (EDHS). Sample sizes of study population were 12,845 in 2005 and 28,532 in 2011. SAS-callable SUDAAN was used provide descriptive characteristics of socio-demographic characteristics and independent variable of HIV-related knowledge, attitude, and behavior. The binary and multivariable logistic regression analysis was conducted to assess changes in HIV-related knowledge, attitude, and behavior and, association between these factors and HIV status. For all results, statistical significant were determined if there were no overlap in the 95% CI of the percentages being compared. RESULTS: There was no difference in correct comprehensive knowledge of HIV between 2005 and 2011. However, there was significant change in knowledge of Mother to Child transmission (MTCT) of HIV, accepting attitude towards people living with HIV (PLWH) and sexual behavior between 2005 and 2011. Respondents who had high level of knowledge of MTCT increased from 40.2% in 2005 to 71.0% in 2011. Likewise, respondents with high level of accepting attitude towards PLWH also increased from 3.9% to 10.8%. Besides, in 2011 fewer people had started sex before the age of 15 years old, and more people knew sources of condoms in comparison to 2005 However the percentage of people who had multiple sexual partners increased from 1.2% to 1.8% between 2005 and 2011 respectively. The study also found significantly protective association between HIV positive status and having low or medium level of knowledge of MTCT of HIV (OR 0.08 or 0.78) and accepting attitude towards people living with HIV (OR 0.12 or 0.48). In contrast, HIV infection was significantly associated with having multiple sexual partners (OR 4.49). Conclusion: Efforts deployed by Ethiopian government and other international organizations in response to HIV/AIDS epidemics have had success in terms of improving MTCT knowledge of HIV, accepting attitude towards PLWH, knowledge of sources of condom and sexual debut between 2005 and 2011. Surprisingly, we did not find an evidence of high level of HIV knowledge to be protective against HIV infection in the current study. Therefore continuous intervention is recommended to seal the gap between knowledge and sexual practices that may influence safer sexual behavioral changes.