Generally, Industries with high contributions to carbon emission are more focused to reduce CO2 emission. Cement production is one example of such high emitting industries. CO2 emissions from the cement industry plays an important role to the global climate change with severe impact on human life, environment and economy globally. Considering that the cement industry is responsible for about 5 % of the total CO2 emitted connected to human activities, a solution to mitigate CO2 emissions is needed . Most of the CO2 from cement production is emitted from the fuel combustion inside the rotary kiln process, the calcination process of limestone and the required power generation. Therefore any material that can replace clinker in cement formulation would contribute significantly to mitigate CO2 emissions. Supplementary Cementitious Materials are a good examples of these materials. In this paper the performance of different blended cements were investigated and the amount of CO2 reduced is calculated based on Calcium Nitrate (CN) dosages needed to compensate the performance loss and the ratio of blends replaced.