The Proceedings of the Global Symposium on Soil Organic Carbon 2017 (GSOC17) presents the abstracts of all scientific presentations held during the GSOC17. 103 oral presentations and 35 poster presentations built the core of this event triggering fruitful discussions on the state-of-science in measuring, preserving and enhancing soil organic carbon in different soils of the world. The GSOC17 took place from 21 to 23 March at FAO Headquarters and was structured in three themes: Theme 1: Monitoring, mapping, measuring, reporting and verification (MRV) of SOC Theme 2: Maintaining and/or increasing SOC stocks for climate change mitigation and adaptation Theme 3 - Managing SOC in soils with high SOC - peatlands, permafrost, and black soils; in grasslands, and livestock production systems; and in dryland soils.