Ongoing climate change has been a major global challenge since the 1880s. Sequestration of carbon(C) in rangelands ecosystems could provide a net carbon sink to offset increases in atmospheric C in global scale. This research is aimed at estimating the above-ground biomass carbon sequestration potential in Iran. For this purpose, total rangelands area and productivity data were extracted from the annual reports of Agriculture Statistical Pocketbook (2006-2013) of the country. Then productivity data was used to calculate above-ground C storage per province. The maximum and minimum rangeland areas were observed in Sistan and Baluchestan and Mazandaran (Nowshahr) Provinces, respectively. Maximum above-ground biomass C storage was about 1.07 Mg Chay in Fars Province. The minimum amount occurred in Qom province with only 0.023Mg C ha y. In summary, mean carbon CO2fixation was about 0.25 Mg C ha yin Iran’s rangelands from 2003 to 2013. Considering the total rangeland area(≈ 84.8 million hectare) and productivity of Iran, 11770.011 Gg C y carbon is stored in aboveground biomass annually providing at least 5885 Gg organic C sequestration potential.