Reducing emissions from deforestation and forest degradation in developing countries, the role of conservation, sustainable management of forests and enhancement of forest carbon stocks (REDD+) has arisen as a key issue in the international climate change negotiations. The efforts have already initiated in many developing countries including India as a global partner in mitigating the climate change through afforestation/reforestation programmes. Under Green India Mission and National Afforestation programme, India has targeted to increase the tree cover by 10 Mha in different land use systems between 2010 and 2020. There is huge knowledge gap on impact of land use practices on C sequestration potential. This paper compares C stocks in three land use systems viz. forest, plantation and agriculture under sub-humid tropics of eastern India. Results revealed that the amount of total carbon stock was comparatively higher in forest followed by plantation and Agroforestry system. The total C stock was lowest in the agriculture land. The difference in carbon stock across land use types are the primary consequences of variation in the vegetation biomass and the soil organic matter. Most of the soil organic C and the fine root carbon was concentrated in the upper 30 cm soil depth and decreased with soil depth. The study indicates that a relatively large amount of carbon lost due to conversion of forest in to agriculture land in the past. Therefore, conservation and sustainable management of forests are recommended to improve C stocks. Similarly, Agroforestry land management practises are suggested in degraded agricultural lands for enhancing the carbon sequestration.