More than 175 million landmines have been deployed since the end of World War II, including > 65 million since 1980. They differ from other weapons by remaining active in the ground long after hostilities have ended. They lie in fields and woodlands, alongside roads and footpaths, and in villages, creating a humanitarian problem with social, economic, and environmental dimensions. In addition to the threat from landmines, many areas of former conflict are contaminated by sub-munitions, unexploded ordnance, discarded weapons, improvised explosive devices (IEDs) and other hazardous debris of war. The victims of landmines and unexploded ordnance inevitably are the poorest and most vulnerable members of societies. It is the subsistence farmer, nomads and their herds, and fleeing refugees who are most affected. Economic necessity forces people to enter known mined areas in search of food and water, to graze livestock, or to gather thatch for their homes. Because landmines are designed to maim, their victims often require extensive treatment for long periods of time. The first aid administered to victims often is rudimentary; in some cases, inappropriately applied tourniquets result in amputations that otherwise might not have been necessary. Much has been achieved since the international community first was made aware of the threat from landmines in countries emerging from conflict in the 1990s. Over the past 20 years, the work of a few non-governmental organizations (NGOs) operating independently in Afghanistan, Angola, and Cambodia has developed into an international program involving the United Nations, the national authorities of 78 mine-affected countries, donor governments, and < 100 NGOs and demining companies. However, more must be done to develop sustainable national capacities. It is particularly necessary for the international community to assist national authorities develop effective and affordable local medical and rehabilitation capabilities.