UNMAS was established in 1997 to serve as the UN focal point for mine action and to support the UN's vision of "a world free of the threat of landmines and unexploded ordnance, where individuals and communities live in a safe environment conducive to development, and where mine survivors are fully integrated into their societies." UNMAS collaborates with partners to ensure an effective, proactive, and coordinated response to the problems of landmines and explosive remnants of war, including cluster munitions. 

UNMAS maintains an office in Geneva. Geneva’s standing as a global hub for humanitarian organizations makes it an ideal base for UNMAS outreach. UNMAS works with a broad set of partners based in Europe and beyond to protect people living in humanitarian emergencies from explosive ordnance and realize the rights of victims. The UNMAS Geneva office also promotes the integration of mine action into humanitarian processes through the Global Protection Cluster.

It represents UNMAS in key humanitarian, human rights, peace, disarmament events and treaty meetings. In addition, it builds partnerships with Member States and international organizations to mitigate the risk of explosive ordnance. Every year, UNMAS organizes the biggest mine action convention in the world, the International Meeting of Mine Action National Directors and United Nations Advisers (NDM-UN) in partnership with the Geneva International Centre for Humanitarian Demining (GICHD).