We used land-cover maps and active fire detection based on satellite imagery to evaluate the rates and spatial distribution of peatland deforestation in Southeast Asia from 1990 to 2010. Over this time period, the proportion of forest cover in the peatlands of Peninsular Malaysia, Sumatra, and Borneo fell from 77% to 36%. After two decades of extensive deforestation (31 000 km2; 4.9% yr−1) strongly associated with fire activity, Sumatra has been left with just 28% of its historical forested peatlands. If peatland deforestation is allowed to continue at current rates, the Southeast Asian peat swamp forests will disappear by around 2030. This will have serious consequences for the local communities that rely on the environmental services provided by peat swamp forests, will lead to the extinction of peat swamp forest species endemic to this region, and will contribute to global carbon emissions.